题目内容
脱式计算,能简算的要简算.
1.25×4.6×8 | 4.58×0.32-0.94 | (0.8+8)×0.125 | 0.65×201 | 9.7×5.6+9.7×4.4. |
分析:(1)运用乘法交换律简算;
(2)先算乘法,再算减法;
(3)运用乘法分配律简算;
(4)先把201分解成(200+1),再运用乘法分配律简算;
(5)运用乘法分配律简算.
(2)先算乘法,再算减法;
(3)运用乘法分配律简算;
(4)先把201分解成(200+1),再运用乘法分配律简算;
(5)运用乘法分配律简算.
解答:解:(1)1.25×4.6×8,
=1.25×8×4.6,
=10×4.6,
=46;
(2)4.58×0.32-0.94,
=1.4656-0.94,
=0.5256;
(3)(0.8+8)×0.125,
=0.8×0.125+8×0.125,
=0.1+1,
=1.1;
(4)0.65×201,
=0.65×(200+1),
=0.65×200+0.65×1,
=130+0.65,
=130.65;
(5)9.7×5.6+9.7×4.4,
=9.7×(5.6+4.4),
=9.7×10,
=97.
=1.25×8×4.6,
=10×4.6,
=46;
(2)4.58×0.32-0.94,
=1.4656-0.94,
=0.5256;
(3)(0.8+8)×0.125,
=0.8×0.125+8×0.125,
=0.1+1,
=1.1;
(4)0.65×201,
=0.65×(200+1),
=0.65×200+0.65×1,
=130+0.65,
=130.65;
(5)9.7×5.6+9.7×4.4,
=9.7×(5.6+4.4),
=9.7×10,
=97.
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
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