题目内容
【题目】递等式计算,能简算的写出简算过程.
(1) ×5+ ×11
(2)21×12×( + )
(3) ÷7+ ×
(4) × ÷ ×
【答案】
(1)解: ×5+ ×11
= ×7+ ×11
= ×(7+11)
= ×18
=10
(2)解:21×12×( + )
=21×12× +21×12×
=3×12+3×21
=3×(12+21)
=3×33
=99
(3)解: ÷7+ ×
= × + ×
=( + )×
=1×
=
(4)解: × ÷ ×
= ÷ ×
= ×
=
【解析】(1)根据乘法的性质,原式变为 ×7+ ×11,再运用乘法的分配律简算;(2)根据乘法分配律进行简算;(3)把除法变乘法,再根据乘法分配律进行简算;(4)从左向右运算顺序计算即可.
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