题目内容
能简算的简算
(1)÷4× | (2)÷÷ | (3)÷+ |
(4)15÷÷ | (5)(-)÷ | (6)×+. |
解:(1)÷4×,
=××,
=;
(2)÷÷,
=××3,
=,
=4;
(3)÷+,
=×99+,
=×(99+1),
=×100,
=20;
(4)15÷÷,
=15×2×,
=45;
(5)(-)÷,
=(-)×24,
=×24-×24,
=22-15,
=7;
(6)×+,
=+,
=.
分析:(1)把除以4化成乘它的倒数来计算,
(2)把除法化成乘它的倒数计算,
(3)把除法化成乘法,运用乘法分配律进行简算计算,
(4)把除法化成乘它的倒数计算,
(5)把除法化成乘它的倒数计算,运用乘法分配律进行简算计算,
(6)先算乘法,再算减法.
点评:考查了分数四则运算的顺序,注意简算.
=××,
=;
(2)÷÷,
=××3,
=,
=4;
(3)÷+,
=×99+,
=×(99+1),
=×100,
=20;
(4)15÷÷,
=15×2×,
=45;
(5)(-)÷,
=(-)×24,
=×24-×24,
=22-15,
=7;
(6)×+,
=+,
=.
分析:(1)把除以4化成乘它的倒数来计算,
(2)把除法化成乘它的倒数计算,
(3)把除法化成乘法,运用乘法分配律进行简算计算,
(4)把除法化成乘它的倒数计算,
(5)把除法化成乘它的倒数计算,运用乘法分配律进行简算计算,
(6)先算乘法,再算减法.
点评:考查了分数四则运算的顺序,注意简算.
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