Question

口算

1 2 × 1 2 =	1 2 × 1 3 =	7 9 ÷ 1 9 =	5 6 ÷ 2 3 =	1- 5 11 =
3 4 ÷ 3 4 =	2 7 - 2 7 =	1÷ 6 13 =	1 6 × 1 2 =	4 5 ÷ 1 5 =
1 4 ÷ 3 4 =	1 3 × 3 8 =	7 9 + 2 9 =1	1 2 + 1 4 =	1 5 + 4 5 =
1 3 × 1 4 =	4 7 ÷ 4 7 =	1- 1 6 =	1 5 ÷ 4 5 =	1 4 ÷ 3 4 =

Answer 1

考点：分数的加法和减法,分数乘法,分数除法

专题：计算题

分析：异分母分数相加减，先通分变成同分母的分数再计算；
分数乘法：分子相乘的积做分子，分母相乘的积做分母，能约分的先约分；
分数除法：除以一个不为零的数等于乘上这个数的倒数．

解答： 解：

1 2 × 1 2 = 1 4	1 2 × 1 3 = 1 6	7 9 ÷ 1 9 =7	5 6 ÷ 2 3 = 5 4	1- 5 11 = 6 11
3 4 ÷ 3 4 =1	2 7 - 2 7 =0	1÷ 6 13 = 13 6	1 6 × 1 2 = 1 12	4 5 ÷ 1 5 =4
1 4 ÷ 3 4 = 1 3	1 3 × 3 8 = 1 8	7 9 + 2 9 =1	1 2 + 1 4 = 3 4	1 5 + 4 5 =1
1 3 × 1 4 = 1 12	4 7 ÷ 4 7 =1	1- 1 6 = 5 6	1 5 ÷ 4 5 = 1 4	1 4 ÷ 3 4 = 1 3

点评：本题考查了简单的分数计算，计算时要细心，注意把结果化成最简分数．