Monday, January 24, 2011, 11:35 A.M. 10th Age Math Class. Class #33 on my “50 Classes or Bust!” expedition. On a frigid day, I am here in a nice toasty Lower School classroom with Mrs. Holt, our Lower School math specialist, and her thirteen eager 10th Age students. After quick homework check, Mrs. Holt announces that it is time for a new activity. Mrs. Holt wants her students to think about math all the time, including when they are getting out supplies. “If your birthday is a prime number, come get a marker and a whiteboard,” she announces, followed by, “If your birthday is a composite number small than 20, come get your supplies,” and so on. The topic of the day is “Russian Peasant Multiplication.” Mrs. Holt shows a video which explains the method: http://www.youtube.com/watch?v=xrUCL7tGKaI
Essentially, one factor is doubled while the other is doubled, “even” rows are crossed out, and then you are left with a “friendlier” addition problem. It is a very interesting method, indeed! The students use remaining class time in pairs to experiment with different combinations and to figure out why this method works mathematically. The students are simultaneously working on their computation while stretching their critical thinking skills! In the final two minutes of class, Mrs. Holt calls up groups of three students for a challenge question. She flips a card, which has a number of dots on it, and then she asks a question to each group of three. The student who first answers correctly wins the round. The questions are challenging--square this number and subtract 5, what is second multiple of this number, square this number and add 9, find two-thirds of this number and multiply by 11—and the students are fast! I am impressed by their speed AND accuracy.
