Question

42点5-45除以18×2点五怎样用简便方法计算

Answer 1

42点5-45除以18×2点五
=42.5-2.5×2.5
=42.5-6.25
=36.25。
(直接计算)。

Answer 2

解: (42.5-45)/(18×2.5)
=(-2.5)/(18×2.5)
=-1/18
或
(42.5-45/18)×2.5
=(42.5-2.5)×2.5
=40×2.5
=100