Wednesday, October 13, 2010

Teaching multi-digit multiplication to my 4th grader

(click on picture for a closer view)

1 comment:

Lsquared said...

Good stuff. I'll be curious to hear if your 4th grader has the same hangup about carrying in multiplication that mine did.

My daughter dug in her heels and would not do the standard algorithm for a good many months because the carrying strategy doesn't make sense (eg: when doing 368x31, and you get to the tens digit, so you're doing 368x30, you first do 30x8=240. So you write down 40 (fine) and then carry the 2 above the 6 in 368, but--why do you put the 2 (hundreds) above the 6 (tens)?! Most kids follow you along with that just fine, but not my kid... We got there, but she spent rather a long time doing the expanded algorithm first. I wish I had known the British algorithm back then, it would have solved so many headaches.