25乘9.9 简便运算
问题描述:
25乘9.9 简便运算
答
25*9.9
=9.9*100/4
=990*4
=247.5
答
25×99
=25×(100-1)
=2500-25
=2475
答
=25×(10-0.1)
=25×10-25×0.1
=250-2.5
=247.5