题目内容
计算: 12.5×7.8×0.8 |
[8.85-(1.5+3.75)]÷1.8 |
4.5-3.2+3.6÷1.44 |
0.91÷0.5÷2.6. |
分析:(1)运用乘法交换律简算;
(2)先算小括号里面的加法,再算中括号里面的减法,最后算括号外的除法;
(3)先算除法,再算减法,最后算加法;
(4)根据连续除以两个数,等于除以这两个数的积简算.
(2)先算小括号里面的加法,再算中括号里面的减法,最后算括号外的除法;
(3)先算除法,再算减法,最后算加法;
(4)根据连续除以两个数,等于除以这两个数的积简算.
解答:解:(1)12.5×7.8×0.8,
=12.5×0.8×7.8,
=10×7.8,
=78;
(2)[8.85-(1.5+3.75)]÷1.8,
=[8.85-5.25]÷1.8,
=3.6÷1.8,
=2;
(3)4.5-3.2+3.6÷1.44,
=4.5-3.2+2.5,
=1.3+2.5,
=3.8;
(4)0.91÷0.5÷2.6,
=0.91÷(0.5×2.6),
=0.91÷1.3,
=0.7.
=12.5×0.8×7.8,
=10×7.8,
=78;
(2)[8.85-(1.5+3.75)]÷1.8,
=[8.85-5.25]÷1.8,
=3.6÷1.8,
=2;
(3)4.5-3.2+3.6÷1.44,
=4.5-3.2+2.5,
=1.3+2.5,
=3.8;
(4)0.91÷0.5÷2.6,
=0.91÷(0.5×2.6),
=0.91÷1.3,
=0.7.
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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