题目内容
合理、灵活地计算.
5.5×17.3+6.7×5.5 | 12.5×32×2.5 | 7.28+3.2÷2.5 | 21.7÷1.25÷0.8. |
分析:(1)根据乘法分配律进行计算,
(2)把32分成8×4,再根据乘法结合律进行计算,
(3)先算除法,再算加法,
(4)根据除法的性质进行计算.
(2)把32分成8×4,再根据乘法结合律进行计算,
(3)先算除法,再算加法,
(4)根据除法的性质进行计算.
解答:解:(1)5.5×17.3+6.7×5.5,
=5.5×(17.3+6.7),
=5.5×24,
=132;
(2)12.5×32×2.5,
=12.5×8×4×2.5,
=(12.5×8)×(4×2.5),
=100×10,
=1000;
(3)7.28+3.2÷2.5,
=7.28+1.28,
=8.56;
(4)21.7÷1.25÷0.8,
=21.7÷(1.25×0.8),
=21.7÷1,
=21.7.
=5.5×(17.3+6.7),
=5.5×24,
=132;
(2)12.5×32×2.5,
=12.5×8×4×2.5,
=(12.5×8)×(4×2.5),
=100×10,
=1000;
(3)7.28+3.2÷2.5,
=7.28+1.28,
=8.56;
(4)21.7÷1.25÷0.8,
=21.7÷(1.25×0.8),
=21.7÷1,
=21.7.
点评:本题主要考查了学生在四则混合运算中灵活运用简便算法的计算能力.
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