题目内容
脱式计算.
500+25×21
(66+210)÷3
21×12×20
450÷9×81.
500+25×21
(66+210)÷3
21×12×20
450÷9×81.
考点:整数四则混合运算
专题:运算顺序及法则
分析:(1)先算乘法,再算加法;
(2)先算加法,再算乘法;
(3)(4)按照从左到右的顺序计算.
(2)先算加法,再算乘法;
(3)(4)按照从左到右的顺序计算.
解答:
解:(1)500+25×21
=500+525
=1025;
(2)(66+210)÷3
=276÷3
=92;
(3)21×12×20
=252×20
=5040;
(4)450÷9×81
=50×81
=4050.
=500+525
=1025;
(2)(66+210)÷3
=276÷3
=92;
(3)21×12×20
=252×20
=5040;
(4)450÷9×81
=50×81
=4050.
点评:整数混合运算的关键是抓住运算顺序,正确按运算顺序计算即可.
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