Question

計算

1 2 × 1 3 =	18× 2 3 =	9 10 × 2 3 =	3 14 × 7 8 =
3 4 × 2 5 =	5 7 ×21=	5 12 × 4 5 =	2 13 ×6=
3 10 × 5 6 =	2 9 ×9=	5 8 × 2 5 =	18× 7 9 =

Answer 1

考點(diǎn)：分?jǐn)?shù)乘法

專題：運(yùn)算順序及法則

分析：根據(jù)分?jǐn)?shù)乘法的計算法則，直接進(jìn)行口算，能約分的先約分計算簡便．

解答： 解：計算

1 2 × 1 3 = 1 6	18× 2 3 =12	9 10 × 2 3 = 3 5	3 14 × 7 8 = 3 16
3 4 × 2 5 = 3 10	5 7 ×21=15	5 12 × 4 5 = 1 3	2 13 ×6= 12 13
3 10 × 5 6 = 1 4	2 9 ×9=2	5 8 × 2 5 = 1 4	18× 7 9 =14．

點(diǎn)評：此題考查的目的是理解掌握分?jǐn)?shù)乘法的計算法則，并且能夠正確熟練地進(jìn)行口算，提高口算能力．