98×0.51 40.7-2.6×9.3 0.8×2.4×12.5 的小数简便计算

问题描述:

98×0.51 40.7-2.6×9.3 0.8×2.4×12.5 的小数简便计算
呵呵,不好意思,我会做了。
麻烦这题,
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Thanks giving Day in the USA is the f▁▁▁▁T▁▁▁▁in November.
New Year's Day is the f▁▁▁▁day of the first m▁▁▁▁▁.
是人教版的同步训练第3页第8题
不知你们有没有

98×0.51
=98×(0.5+0.01)
=49+0.98
=49.98
40.7-2.6 *9.3
=40.7 -2.6*(10 -0.7)
=40.7 -26 +2.6*0.7
= 14.7 +2.6*0.7
=14.7 +2.6*(1 -0.3)
=14.7 +2.6 -0.78
=17.3-0.78
=16.52
0.8×2.4×12.5
=0.8×12.5×2.4
=10×2.4
=24