回复：My daughter's 3rd grade math. Need help...

来源: 于 2010-01-17 23:58:46 [旧帖] [给我悄悄话] 本文已被阅读：次

Why 3rd grade math? Maybe because the "only" operator needed here is addition:


1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
5 10 10 5
15 20 15
35 35
70