Question

计算．

2 5 × 10 11 =	3 14 × 7 15 =	5 9 × 2 15 =
1 3 × 1 5 ×2=	1 7 × 1 9 ×2=	1 9 × 1 11 ×2=
1 3 - 1 5 =	1 7 - 1 9 =	1 9 - 1 11 =

Answer 1

考点：分数乘法,分数的加法和减法

专题：运算顺序及法则

分析：本题根据分数乘法与减法的运算法则计算即可．

解答： 解：

2 5 × 10 11 = 4 11	3 14 × 7 15 = 1 10	5 9 × 2 15 = 2 27
1 3 × 1 5 ×2= 2 15	1 7 × 1 9 ×2= 2 63	1 9 × 1 11 ×2= 2 99
1 3 - 1 5 = 2 15	1 7 - 1 9 = 2 63	1 9 - 1 11 = 2 99

点评：在完成此类题目中，

1

n

-

1

m

=

m-n

nm

．