Thursday, January 2, 2025

Can you Count to 70?

Question: How many males are counted as coming to Mitzrayim with Yaakov? One thing is for sure, it wasn't 70. I still have not been able to figure out how all the numbers worked - who were the 66 mentioned in 46:26 and the 70 in 46:27? 66+3 = 69, the last time I checked. If you add up all of the children and grandchildren, it does come out to 70 but then it should have been 67 and then 70. All that aside, it was not only males who were counted. Dinah is counted along with her brothers which is understandable. Serach bas Asher is counted as well which is slightly more puzzling. One must assume she was not the only granddaughter. From Rashi (46:27) it seems Yocheved was somehow part of the 70 as well.

While I was not able to find anything explaining why these particular women figured in the count as opposed to others, I did see an interesting insight into the pesukim in consideration of that fact. Tzeror HaMor and Emes L'Yaakov both point out a discrepency in the per-wife tallies found in the pesukim. The numbers for Rachel ("arba'ah asar") and Bilhah ("shiv'ah") are of the masculin form. The numbers for Leah ("sheloshim veshalosh") and Zilpah ("sheish esreih") are feminine. They both explain that Leah and Zilpah both had women counted among their offspring - Dinah from Leah and Serach from Zilpah. Therefore their numbers are delivered in feminine. Rachel and Bilhah had no feminine offspring counted and thus their numbers are in masculine.

One might wonder why this is so, considering that the generic plural is usually masculine by default. However, Emes L'Yaakov points out that the word "nefesh" which the number is qualifying is feminine. So the default gender of the number for "nefesh" should be feminine. Rachel and Bilhah were the exceptions.

Friday, December 13, 2024

Goats and Amicable Numbers

Goats and Amicable Numbers

In this week’s parasha, we find Yaakov preparing for his encounter with his twin brother Esav in several ways. Among other preparations, Yaakov sends him gifts consisting of various different kinds of animals. The Torah tells us (Bereishit 32:14–16) how many of each kind of animal Yaakov sent: 200 female goats and 20 male goats; 200 female sheep (ewes) and 20 male sheep (rams); 30 nursing camels with their young; 40 female cows and 10 bulls; 20 female donkeys and 10 male donkeys. What is the significance of these numbers?

In his ספר בעלי ברית אברם, R’ Avraham Azulai provides an explanation for the number of goats, which he attributes to R’ Nachshon Gaon of the 9th century. The total number of goats is 200 + 20 = 220. What significant property does the number 220 have?

Consider the factors of 220, that is, numbers that multiply together to give the product 220. We can factor the number 220 in the following ways:
220 = 1 × 220
220 = 2 × 110
220 = 4 × 55
220 = 5 × 44
220 = 10 × 22
220 = 11 × 20
Now consider only the “proper factors” of 220 – that is, all the factors in the above list, excluding the number 220 itself – and add them up:
1 + 2 + 4 + 5 + 10 + 11 + 20 + 22 + 44 + 55 + 110 = 284
So the proper factors of 220 add up to 284.
We now repeat the process, considering the factors of 284. We can factor the number 284 in the following ways:
284 = 1 × 284
284 = 2 × 142
284 = 4 × 71
Again, we consider only the proper factors of 284 – all the factors in the above list, excluding the number 284 itself – and add them up:
1 + 2 + 4 + 71 + 142 = 220
So the proper factors of 284 add up to 220. Does this number look familiar?

As we have just shown, the numbers 220 and 284 have the property that the proper factors of each number add up to the other number. A pair of numbers with this property is known as a pair of amicable numbers, or according to R’ Nachshon Gaon, מנין נאהב. Apparently it was known to the ancients that in order to gain the love of kings and princes, a person would give one of a pair of amicable numbers as a present, keeping the other number for himself. This is so that the factors of the number given add up to the number kept, and the factors of the number kept add up to the number given. So this is what Yaakov did. He sent Esav 220 goats, and kept 284 for himself.

Wait a minute: The Torah tells us that Yaakov gave Esav 220 goats, but where do we see in the Torah that he kept 284 for himself? Several pesukim later, as Yaakov gives instructions to the servants carrying the gifts, the Torah records (32:21), “כי־אמר אכפרה פניו במנחה ההולכת לפני” – “for he said: I will win him over with the gifts that are being sent ahead.” R’ Nachshon Gaon explains that this sentence contains a hint to the number 284, in the following way. The word אכפרה can be divided in two parts: אכ פרה. When the Torah uses the word אך, it is generally interpreted by the Rabbis to indicate exclusion or reduction. Calculating the numerical value of the second part of the word, פרה, we get: 80 (פ‎) + 200 (ר‎) + 5 (ה‎) = 285. Applying a reduction (indicated by אך) to the value 285 (given by פרה), we obtain a value of 284. This represents the number of goats that Yaakov kept for himself, according to R’ Nachshon Gaon.


Special thanks to Daniel Levenstein for bringing this insight to my attention.

Addendum: Yaakov sent a number of different types of animals. Why were only goats sent in amicable numbers? See an interesting thought from רבנו בחיי which may shed some light on this question.

References:

Leonard Eugene Dickson, History of the Theory of Numbers, Volume I: Divisibility and Primality, Carnegie Institute of Washington: Washington, 1919, p. 39, available at:
http://www.archive.org/stream/historyoftheoryo01dick#page/38/


ר' אברהם ב"ר מרדכי אזולאי, ספר בעלי ברית אברם, published 1873 but existed in manuscript for 300 years previously; pp. 48–49, available beginning at:
http://www.hebrewbooks.org/pdfpager.aspx?req=3997&pgnum=47


הנאהבים והנעימים - על רעות אצל מספרים, in Michlalah Jerusalem College's mathematical journal אלף אפס (ℵ₀):
http://alefefes.macam.ac.il/article/article.asp?n=15
(may not work in all browsers)
(Thanks to Yaaqov Loewinger for this link via Hebrew Wikipedia)

Wednesday, October 16, 2024

How many בקשות in יעלה ויבוא

Since we are about to say יעלה ויבוא numerous times (perhaps as many as 40 times) I figured it would be a good time to explore this:
A friend once approached with an interesting project - to calculate the total number of בקשות in יעלה ויבוא. Now, of course, that's not as simple as it seems. It is not simple addition. It involves a lot of multiplication.
So let's dive into it:

יעלה | ויבוא | ויגיע | ויראה | וירצה | וישמע | ויפקד | ויזכר= 8
(Keep in mind that all the above verbs will apply to all of the following nouns:)
זכרוננו | ופקדוננו | וזיכרון אבותינו | וזיכרון משיח בן דוד עבדך | וזיכרון ירושלים עיר קדשך | וזיכרון כל עמך בית ישראלx 6
= 48
(And then the following modify all of the above:)
|לפניך לפליטה | לטובה | לחן | ולחסד | ולרחמים | לחיים ולשלוםx 7
So the entire first section = 336
זכרנו ה' אלוקינו בו לטובה | ופקדנו בו לברכה | והושיענו בו לחיים טובים + 3
= 339
Now we add the final portion:
ובדבר ישועה | ורחמים= 2
חוס | וחננו | ורחם עלינו | והושיענוx 4
= 8
So the final count is 339 + 8= 347

Wow, 347 בקשות packed into one small תפילה!

Thursday, September 19, 2024

Balancing the Shevatim at Har Grizim and Har Eival

In the fall of 1992, there was a fascinating article concerning this week's parsha written up in Tradition magazine by Rabbi Michael Broyde of Atlanta and Steven Weiner of Los Angeles. I will try to sum up the article as concisely as possible. The pasuk tells us (27:12-13) that the tribes of Shimon, Levi, Yehuda, Yissachar, Yosef and Binyamin stood on Har Grizim for the delivering of the beracha. Reuven, Gad, Asher, Zevulun, Dan and Naftali stood on Har Eival for the delivering of the kelala. The gemara (Sotah 37a) presents a quandary based on a pasuk in Yehoshua that seems to show that the kohanim were in the middle of the two mountains. So how could they be said to have been on Har Grizim? The gemara gives three different answers as to how the kohanim were split up, some below, and some on the mountain (according to two of the answers.) The answer that seems to be most dealt with amongst the meforshim is that those who were 'fit for work' were below with the aron, and those who were not were above. Rashi learns this to refer to those above thirty while the Maharsh"a learns that it is referring to b'nei Kehas who were in charge of the aron.

Now, in dividing the tribes between two mountains, there are 462 different ways to make such a division [12! / 2(6!6!)]. Broyde and Weiner point out a fascinating fact. Taking the most recent census data that we are given in the Torah and dealing with the answer of the gemara that we have discussed, if you examine every single possible formation of the tribes, the actual formation of the tribes is the absolute most even division of the tribes possible. That is, the difference in population between the two mountains is at a minimum with this formation. [I personally wrote a computer program to test it out and it worked. In the article, they include a list of all possible combinations and their respective differences.] What is even more fascinating, is that this works out for both Rashi and the Maharsh"a. And what may be the most fascinating of all is that according to the Maharsh"a, the population on Har Grizim would have been 307,929 and that of Har Eival 307,930. No, that's not a typo. That is a difference of 1! According to both, this is by far the most even division of the tribes.

The next step is what to do with such an impressive observation. What does this tell us? I will leave that for the reader to decide. [In the article, they suggest a parallel to that which we are taught (Kiddushin 40b) that one should always look at the world as if it were half righteous and half guilty and the judgement of the entire world is dependent on him.] But for what it's worth, it is surely an intriguing observation on its own.

The article became the subject of debate in the Spring of 1999 with The Solution to Deuteronomy is not in Numbers, a rebuttal by Sheldon Epstein, Yonah Wilamowsky & Bernard Dickman. This was then followed up by A Mathematical Solution on Terra Firma and a Geographical Explanation on Weak Ground by the original authors.

IMPORTANT UPDATE: Tradition magazine has been gracious enough to make their archives fully available to the public! So following the links above will now allow you to read the articles in their entirety.

Friday, August 2, 2024

Splitting up the Animals

Some time after the victorious military campaign against Midyan, ל"א:כ"ה-מ"ז, all of the booty - humans and animals - is counted and divided in two. One half is designated for the soldiers who fought the war and the other half is for the rest of בני ישראל. Of the half that went to the soldiers, one out of 500 was to be given to אלעזר. Of the half that went to the rest of the nation, one out of 50 was given to the לויים.

There are a number of puzzling nuances in this chapter. First the totals of the sheep, cattle, donkeys and humans are tallied. Then the halves to the soldiers are counted as well as אלעזר's portion. The halves to the rest of the nation, although exactly the same as the halves to the soldiers are counted. It is recounted that משה distributed the portion for the לויים but no count is given. Lastly, אלעזר's portion is said to be "from the humans, from the cattle, from the donkeys and from the sheep." The same phrase is repeated with regards to the portion of the לויים but the words מכל הבהמה, from all of the animals, is added.

נצי"ב, in העמק דבר, suggests that מכל הבהמה includes other species of animals that were brought back that were fewer in number. Since they were fewer than 1000, there would not have been enough to give אלעזר even one. Therefore, this phrase is left out of the command of אלעזר's portion and these animals' numbers are not significant enough for the תורה to recount.

A fascinating approach is offered in the name of ר' שלמה הכהן מווילנא. Elazar's portion is referred to in פסוק כ"ט as a 'תרומה לה. One of the laws of תרומה is that one may not separate from one species as תרומה for another. Therefore, אלעזר's portion was required to be one out of every 500 of each animal. However, this was not a requirement with the portion of the לויים and it was sufficient to give them 1/50 of all the animals combined. That is the meaning of מכל הבהמה. The לויים were given 1/50 of all the animals. And that is why the תורה does not go into any detail concerning the division for it was not exact.

Friday, July 26, 2024

No Population Increase

I was discussing the census numbers with someone one שבת. An interesting question was posed regarding the lack of an increase in population over the different censuses that were taken throughout the years in the מדבר. This question is really better suited for פרשת פינחס which takes place towards the end of their journey with still no increase. 

One obvious question is that there should have been many children born over the course of the first 20 years in the מדבר who would be counted by the last census. I've heard some answers to that question which I'd rather not go into at this juncture. The less obvious but more difficult issue is the children that came out of מצרים. As we've pointed out in a previous post, the first born made up approximately 4% of the population which means each family was exceedingly large. It would probably be a gross understatement to suggest that each family consisted of at least 10 male children. Let's even go so far as to say 5, to take into account children who were already counted in the original census. Even though the original 600,000 included a number of different generations it still seems that by all accounts, there should have already been millions of male children not counted in the first census. So where did all these millions go?

The Probability of the Goral


In pasuk 26:54, the Torah explains how the land was divided amongst the tribes. Rashi explains exactly how the lots were picked to determine each tribe's portion.

Even though the portions were Divinely predetermined, a lot-drawing process was used to assign each tribe their portion. Rashi explains that one drum was filled with 24 pieces of paper. On 12 pieces of paper were written the names of the 12 tribes. On the other 12 were written the 12 portions that were to be assigned to the tribes. Each Nasi approached the drum and picked out two pieces of paper. One paper had the name of his tribe written on it and the other the prescribed portion of land in Eretz Yisrael. The purpose of this exercise was to prove the Divinity of division plan that allotted each tribe its portion and appease any tribe who felt it might be unfair. As such, I believe that a miracle of this type may be more greatly appreciated if we knew exactly how unlikely it would have been to happen naturally.

Suppose we had a prescribed list of which portion was to be assigned to which tribe. What would be the odds of each Nasi picking out both the name of his tribe and also the corresponding piece of land that had already been prescribed? Let us start with the first Nasi. He has 24 pieces of paper to choose from. He must pick two specific pieces of paper out of the drum. The odds of taking the first one correctly would be 1/24 and then the odds of taking the second correctly would be 1/23. However, since the two papers were taken together, the order does not matter. The rules of probability theory state that if the order of the choices is not relevant, than the odds must be multiplied by the number of possible sequences which, in this case, is two. So the odds of the first Nasi picking the right pieces is 2/(24 x 23). With 22 pieces of paper remaining, the odds of the second Nasi picking correctly will be 2/(22 x 21). And so on. The last Nasi's odds will be 2/(2 x 1) which is 1. That means that he will definitely pick the right ones. That is understandable. By the rules of probability theory, in order to find the odds of all the Nesiim picking correctly, we must multiply each Nasi's odds together. Thus, the odds may be generalized as
212
(24 x 23 x 22 x 21...x 2 x 1)

24 x 23 x 22 x 21....x 2 x 1 is referred to as 24 factorial and expressed as 24! Thus the final expression is 212/24!. When all is totalled, the odds of the draw falling out exactly as planned without any Divine intervention would have been one in 151,476,000,000,000,000,000.

This calculation is based on Rashi's explanation in the chumash according to the Midrash Tanchuma. However, Rashi (actually written by Rashbam, Rashi's grandson,) in the gemara (Bava Basra 122a) states clearly that two drums were used. This will alter the calculation somewhat. The first Nasi would have a 1/12 chance of picking his tribe's name from the tribe drum and a 1/12 chance of picking the correct portion from the portion drum. The fact that the order does not matter will not affect the odds in this case because the choices are made from two separate groups. The odds for both drums are multiplied and thus, the first Nasi's odds will be 1/122. The odds of the second Nasi will be 1/112. And so on. The total odds will be:

1
122 x 112 x 102 x 92 x 82 x 72 x 62 x 52 x 42 x 32 x 22 x 12


This can, in fact, be simplified as 1/12!2. The final odds will be one in 229,442,532,802,560,000. This is approximately 660 times more probable than the odds according to Rashi on the chumash.


Just to get an idea of the extent of this improbability, the odds of winning the Powerball Jackpot are approximately one in 175 million. That is over 1.3 billion times more likely to happen than this, according to Rashi on the gemara, and over 860 billion times more likely according to Rashi on the chumash. The odds of getting fatally hit by lightning in a given year are approximately 1 in 2.4 million. In fact, it is more likely for one to win the Powerball twice in one week or get fatally hit by lightning two-and-a-half times in one year than for the goral's results to have been produced naturally. This is a veritable testimony to the extent of the miracle that occurred and the Divinity of the apportioning of Eretz Yisroel to the twelve tribes.

תשע"ד: A similar drawing came up this week in דף יומי on :תענית כ"ז regarding the גורל used to determine the order of the משמרות in the בית שני. According to רש"י's understanding, there was a similar miracle at play. The probability associated with that drawing is discussed here.

1

Friday, July 19, 2024

Counting the Judges


In the end of Parshas Balak, (pasuk 25:5), Moshe passes on HaShem's command to carry out justice upon those who worshipped Ba'al Pe'or.

Rashi states that there were 88,000 "Dayanei Yisroel" and cites the gemara at the end of the first perek of Sanhedrin. However, the gemara over there clearly calculates the number of Dayanei Yisroel to be 78,6001. Of course the obvious easy way out would be to say that there is an error in our version of Rashi, which would require only the replacing of the word shemonas with the word shiv'as to get close enough to the true number. This, in fact, seems to be the version of Rashi that the Ramban had. However, whenever this is avoidable it is best not to rely on such an answer and to justify our reading of Rashi. But is it avoidable in this instance?

Perhaps, it is possible that Rashi is not referring to the actual number given in Sanhedrin but to the calculation done there. Just as when B'nei Yisroel were 603,550 the number of dayanim was 78,600 the number of dayanim based on B'nei Yisroel's current population would be around 88,000. The next step, then, is to calculate what population would require 88,000 dayanim. Being that the dayanim included judges of groups of 1000, 100, 50 and 10 the following equation is given:
88,000

= (x/1000) + (x/100) + (x/50) + (x/10)
(where x = total population)
= (100x + 20x + 10x + x)/1000
(multiplying by 1000/1000, i.e. 1)
= 131x/1000
(131 judges per 1000 citizens)
x= 88,000,000/131
x

= 671,755
(rounded down)


A population of close to 672,000 is needed to necessitate 88,000 dayanim. This is an odd number since none of the recorded censuses rendered a number anywhere near this. But as clearly shown in the very Rashi in question, there was to be a large population decrease before B'nei Yisroel would reach the figure of 601,730 given in Pinchas. To justify this figure of 671,755 we must account for 70,000 lost lives. The only definite casualty count we are given is the 24,000 who perished in the plague following the worship of Ba'al Pe'or. That still leaves 46,00 lives unaccounted for. Starting from Beha'aloscha there were a number of catastrophic incidents recorded in which many fell from B'nei B'nei Yisroel. However, many of these may not be considered in this particular calculation. If B'nei Yisroel did in fact reach a population as large as we are suggesting then it must have happened gradually from the time of the census in Bemidbar to the time that they began their decline to the figure given in Pinchas. Therefore, since the individual plagues from Beha'aloscha to Korach were still in the second year and, for the most part, immediately after the census in Bemidbar we may not consider them in the decline of the population toward the figure of 601,730.


We are left, then, with only three incidents to consider. The first is the episode following the death of Aharon when B'nei Yisroel began to return toward Mitzrayim and B'nei Levi ran after them (see Rashi 26:13). The Yerushalmi records that only eight (or seven, see Rashi and the Yerushalmi inside) families were wiped out from Yisroel in that incident. This would seem to represent a significant loss but perhaps not 46,000.


The second is the episode with the snakes (Bemidbar 21) where, as recorded in the Mishna (Rosh HaShanah 29a), those who were bitten and did not have appropriate kavana when shown the copper snake perished. Here, too, there is no significant loss recorded but only that proper kavana was required for the snake to cure you. Before the cure, however, the pasuk states (pasuk 6) that a great multitude perished from Yisroel. We are not given any further information, though, on the number of casualties2.


Finally, there is the plague of Ba'al Pe'or. That leads into a discussion as to what in fact transpired besides the loss of 24,000 in the plague. From the fact that the Torah refers to a magefa, it is doubtful that this refers to those killed by the shoftim. So how many people did the shoftim kill? The Ramban (on this pasuk) quotes a Yerushalmi, the simple reading of which implies that each shofet killed two men as commanded by Moshe. This would render well over 150,000 casualties. Ramban, however, concludes that the figure given by the Yerushalmi is just referring to how many would have been killed had Moshe's command been carried out but in the end the shoftim never had a chance to do so and they didn't kill a soul. Perhaps it is possible to take this idea of the Ramban that the shoftim were interrupted before having a chance to complete their mission, but to suggest that they had already begun to carry it out when they were interrupted. With or without such a supposition, one could suggest that in some way, these three incidents combined for a grand total of 46,000 fatalities. The other 24,000 died in the magefa. Now we have accounted for all 70,000 lives and all the figures work out.


Nevertheless, it is doubtful that Rashi actually wrote 88,000 and had this convoluted calculation in mind. Rather, it is more reasonable to assume that this version of Rashi is a mistake and that he originally wrote 78,000, particularly because the Ramban had such a reading of Rashi. However, I am not the first to try and justify the figure of 88,000. The Margaliyos HaYam on the gemara in Sanhedrin cites the sefer Techeles Mordechai who offers a calculation based on a population of 603,550:

603shoftim over a thousand
6,035shoftim over a hundred
12,071shoftim over fifty
60,355shoftim over ten
70zekeinim
276(12x23 small Sanhedrin for each tribe)
72(12x6 Nesi'im for each tribe)
8,580Levi'im
=88,002

There are a number of details involved in this figure that may be questionable. Firstly, we have previously determined that before the sin of Ba'al Pe'or the population was at least 625,000. Also, there is no source that indicates that all these different parties were included in the term "Dayanei Yisroel." The gemara in Sanhedrin certainly did not include them. Then Rashi's comment on this pasuk would have absolutely nothing to do with the gemara and from the text of Rashi it seems that Rashi himself cited the gemara in Sanhedrin. So, the conclusion remains that the proper reading of Rashi is most likely 78,000 rather than 88,000.


1Although it is not the subject of this piece, it is interesting to note the various discussions concerning the calculation in Sanhedrin. The Yad Ramah and one opinion in Tosafos state that the shoftim were all over 60 and were not part of the general population. Another opinion in Tosafos states that the shoftim of 50 were taken from the shoftim of ten, the shoftim of 100 were taken from the shoftim of 50, etc. This, however, is not in accordance with the Yerushalmi quoted here by the Ramban. See also Margaliyos HaYam who raises a number of interesting questions regarding the figure given there. It bothered me, though, that the calculation is based on 600,000 not 603,550 which would render a different total.
2The Zohar in Parshas Balak cites an opinion that this pasuk is referring to Tzelafchad alone for he was the leader of his tribe (Source: Ta'ma D'Kra, R' Chaim Kunyevsky)

Friday, June 21, 2024

Piles of Quail

In this week's parsha, we have the episode of the quail that fell outside of the camp. The pasuk (11:32) recounts that the one who gathered the least gathered 10 mounds of quail. The GR”A has a fascinating calculation to figure out how this number was reached. It is assumed that the one who gathered the most would have been the one whose tent was at the outskirts of the camp because the quail fell outside the camp. The one who gathered the least would be the one whose tent was the furthest inside the camp. The gemara (Berachos 54b) tells us that the camp was 3 parsa by 3 parsa. Therefore, someone who lived on the very inside of the camp would have to walk three parsa in order to get a pile of quail, one and a half there and one and a half back. The gemara (Pesachim 93b) also tells us that a regular man can walk 10 parsaos in a day (not including the night). According to the pesukim, the quail was collected for a day, a night and a day, a total of one and a half days. This would give the average man enough time to walk 30 parsaos - ten the first day, ten during the night, and ten again the next day. This would allow one who lived in the centre of the camp to travel back and forth ten times. That is how the pasuk arrived at this number.

Friday, June 7, 2024

Tens and Ones

In Biblical Hebrew, numbers containing both tens and ones are usually written with the ones first, followed by the tens. To cite one of many examples in Bemidbar, the census figure for Reuven is 46,500, written in pasuk 1:21 as "ששה וארבעים אלף וחמש מאות", literally "six and forty thousand and five hundred", in contrast to the usual English way of speaking, which would be "forty-six thousand".

The first question is, why is this the case.

Furthermore, I noticed something this week that I don't recall ever noticing before: In one instance in the parasha, this style is violated. Pasuk 2:9 gives the total of the Eastern Camp, including the tribes of Yehuda, Yissachar, and Zevulun. The number is 186,400, written as follows:


כָּל-הַפְּקֻדִים לְמַחֲנֵה יְהוּדָה, מְאַת אֶלֶף וּשְׁמֹנִים אֶלֶף
וְשֵׁשֶׁת-אֲלָפִים
וְאַרְבַּע-מֵאוֹת--לְצִבְאֹתָם; רִאשֹׁנָה, יִסָּעוּ.


"... a hundred thousand and eighty thousand and six thousand and four hundred ..."

This is a clear departure from the usual style, which would have been "ששה ושמנים אלף", "six and eighty thousand". I am not aware of any other such departure from the usual style. Any ideas why this is?