Friday, August 16, 2013

Japanese Math

Let me see if I can explain how Japanese children are taught to multiply two two-digit numbers.

36 times 12. Draw three lines, then skip a bit, then 6 lines all going up and down.

Then sideways you got one line, then skip a lot, then 2 more lines.

1. In one corner the one line crosses the first three lines…that’s 3 (or 300)
2. Then the one line crosses the 6 lines…that’s 6 (or 60)
3. Diagonally from the 6 the two lines cross the three lines for 6 more (or 60 more)
4. Then in the other corner the two lines cross the six lines 12 times (or 12 more).

300+ 60 + 60 + 12 = 432

You’re supposed to be able to draw one circle around the first 3 (hundreds), a second long circle around the two groups of 6 each at each corner (tens), and a third circle around the 12 in the other corner (ones).   

Get it?

No comments: