题目内容
能简便的要简便计算 | (7.6-3.6÷2)×1.5 |
45×(+-0.6) | |
0.625×0.5++×62.5% |
解:(1)÷[-(+)]-,
=÷[-]-,
=÷-,
=×-,
=-,
=1;
(2)(7.6-3.6÷2)×1.5,
=(7.6-1.8)×1.5,
=5.8×1.5,
=8.7;
(3)-÷,
=-×
=-,
=;
(4)÷9+×,
=×+×,
=(+)×,
=×,
=;
(5)+(-)÷,
=+÷,
=+×,
=+,
=;
(6)÷[-(1-)],
=÷[-],
=÷,
=×10,
=;
(7)+×+
=++,
=;
(8)45×(+-0.6),
=45×+45×-45×0.6,
=35+12-27,
=20;
(9)0.625×0.5++×62.5%,
=0.625×0.5+0.625+0.5×0.625,
=(0.5+1+0.5)×0.625,
=2×0.625,
=1.25.
分析:(1)先算小括号内的,再算中括号内的,然后算括号外的除法,最后算减法;
(2)先算括号内的除法,再算括号内的减法,最后算括号外的乘法;
(3)先算除法,再算减法;
(4)把除法改为乘法,运用乘法分配律简算;
(5)先算括号内的,再算括号外的除法,最后算加法;
(6)先算小括号内的,再算中括号内的,最后算括号外的;
(7)先算乘法,再算加法;
(8)运用乘法分配律简算;
(9)把分数和百分数化为小数,运用乘法分配律简算.
点评:考查了四则混合运算的运算顺序以及简便计算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
=÷[-]-,
=÷-,
=×-,
=-,
=1;
(2)(7.6-3.6÷2)×1.5,
=(7.6-1.8)×1.5,
=5.8×1.5,
=8.7;
(3)-÷,
=-×
=-,
=;
(4)÷9+×,
=×+×,
=(+)×,
=×,
=;
(5)+(-)÷,
=+÷,
=+×,
=+,
=;
(6)÷[-(1-)],
=÷[-],
=÷,
=×10,
=;
(7)+×+
=++,
=;
(8)45×(+-0.6),
=45×+45×-45×0.6,
=35+12-27,
=20;
(9)0.625×0.5++×62.5%,
=0.625×0.5+0.625+0.5×0.625,
=(0.5+1+0.5)×0.625,
=2×0.625,
=1.25.
分析:(1)先算小括号内的,再算中括号内的,然后算括号外的除法,最后算减法;
(2)先算括号内的除法,再算括号内的减法,最后算括号外的乘法;
(3)先算除法,再算减法;
(4)把除法改为乘法,运用乘法分配律简算;
(5)先算括号内的,再算括号外的除法,最后算加法;
(6)先算小括号内的,再算中括号内的,最后算括号外的;
(7)先算乘法,再算加法;
(8)运用乘法分配律简算;
(9)把分数和百分数化为小数,运用乘法分配律简算.
点评:考查了四则混合运算的运算顺序以及简便计算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.
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