Parshat Matot: What's half of 675,000?

In this week's parsha, the Jews have to divide spoils after defeating Midian, which offers great opportunities for math!

In this D'var Torah that I wrote for the Center for Modern Torah Leadership, I cover an Ohr HaChayim that differentiates between part-to-part and part-to-whole ratios and a Malbim that references equivalent fractions. We also sneak in some thoughts about division, counting and parts of different wholes.

My favorite line is Rav Eliyahu Munk's translation of Ohr HaChayim:

"The Ohr Hachaim accepts Ramban’s question, writing, “למה האריך כל כך בפרטי החשבון בדבר שיכול כל הבא למנות לידע ”, hilariously translated by Rav Eliyahu Munk as “Who amongst us cannot figure out what half of a total of 675,000 sheep amounts to?”"

Who, indeed?

It's not usually taught in Jewish day schools, but there's a lot of math in Matot!

Enjoy. Shabbat shalom!

Rational numbers are like midrashim

I enjoyed reading Ilana Kurshan's memoir "If All the Seas Were Ink."

I especially appreciated how she compares midrash to rational numbers. Join the discussion here.

Lessons Learned: Graphing an Israeli flag on a coordinate plane

Last year, I debuted this "graph an Israeli flag on the coordinate plane" activity in my 6th grade classes. This activity was very successful! I would estimate it takes about 30 minutes to make one graph (I had 15, so two different groups of students made each graph.) Not every group finished, but I just needed a few good finished copies. The kids enjoyed the activity regardless, though some of them got frustrated when they started with markers, made errors and then could not fix them.

Supplies are essential! I did not have enough yardsticks (you need one per group) and blue markers. You need 1 thin blue marker per group and 1 thick blue marker per person. Crayola does not appear to sell boxes of thin markers that are all blue. You don't actually need to do much with the thin markers. They are primarily useful to number the axes.

It is important for visibility that the Magen David is made with a thick marker. You can outline with a thin marker, but you'll need to trace over with a thick one for it to be seen, as you can tell in the difference between these two graphs.

One last change: I used axes that were not blue, and I thought it looked good. The goal of contrast was that the axes not impede the visual of the Magen David.

This was fun. I'm hoping to do it again this year!