用简便方法计算下面各题751-299 11.8*41-82*9/10

问题描述:

用简便方法计算下面各题
751-299 11.8*41-82*9/10

751-299
=751-(300-1)
=751-300+1
=451+1
=452
11.8×41-82×9/10
=(10+1.8)×41-41×2×9/10
=10×41+1.8×41-41×9/5
=410+1.8×41-41×1.8
410