Question

用简便方法计算。5.28-1.18+14.72-3.82和着相似的题做十道。

能用简便方法计算的用简便方法计算． 18.5-3.21-4.79 4.8+3.72+4.2+16.28 4.5×0.7+5.5×0.7 （8-0.8）×1.25 14.2×99+1.42 8.8×0.6+0.32

Answer 1

（1）18.5-3.21-4.79
=18.5-（3.21+4.79）
=18.5-8
=10.5

（2）4.8+3.72+4.2+16.28
=（4.8+4.2）+（3.72+16.28）
=9+20
=29

（3）4.5×0.7+5.5×0.7
=0.7×（4.5+5.5）
=0.7×10
=7

（4）（8-0.8）×1.25
=8×1.25-0.8×1.25
=10-1
=9

（5）14.2×99+1.42
=14.2×99+14.2×0.1
=14.2×（99+0.1）
=14.2×99.1
=1407.22

（6）8.8×0.6+0.32
=5.28+0.32
=5.6