Question

几道简算题4

1．1/17×4/9＋5/17×1/9
2．1/7×3/4＋3/7×1/6＋6/7×1/12
3．5/9×79又16/17＋50×1/9＋1/9×5/17
4．5/17×3/8＋1/15×7/16＋1/15×3又1/2

Answer 1

1．1/17×4/9＋5/17×1/9
= 1/17×4/9＋1/17×5/9
= 1/17×（4/9＋5/9）
= 1/17

2．1/7×3/4＋3/7×1/6＋6/7×1/12
= 3/7×1/4＋3/7×1/6＋3/7×1/6
= 3/7×（1/4＋1/6＋1/6）
= 3/7×7/12
= 1/4

3．5/9×79又16/17＋50×1/9＋1/9×5/17
= 5/9×（179又16/17＋10＋1/17）
= 5/9×90
= 50

4．5/17×3/8＋1/15×7/16＋1/15×3又1/2
= 7/15×3/8＋7/15×1/16＋7/15×1/2
= 7/15×（3/8＋1/16＋1/2）
= 7/16

Answer 2

1．
1/17×4/9＋5/17×1/9=(1×4+5×1)/（9×17)=9/（9×17)=1/17
2.
1/7×3/4＋3/7×1/6＋6/7×1/12=1/7×9/12+3/7×2/12+6/7×1/12
=(1×9+3×2+6×1)/(7×12)=21/(7×12）=1/4
3.
5/9×79又16/17＋50×1/9＋1/9×5/17
=
4.