Question

99.9×0.8+11.1×1.8怎样简便运算？

Answer 1

乘法分配律的运用
可以把99.9写成11.1×9，让9和0.8相乘，也可以把1.8写成9×0.2，让9和11.1相乘，计算如下
99.9×0.8+11.1×1.8
=99.9×0.8+11.1×9×0.2
=99.9×0.8+99.9×0.2
=99.9×(0.8+0.2)
=99.9×1
=99.9

Answer 2

99.9*0.8+11.1*1.8
=11.1*(9*0.8+1.8)
=11.1*(7.2+1.8)
=11.1*9
=99.9

Answer 3

=11.1X9X0.8+11.1X1.8
=11.1X（9X0.8+1.8 ）
=11.1X9
=99.9

Answer 4

=（100-0.1）x0.8+11.1x（1+0.8）
=（100-0.1）x0.8+11.1×1+11.1x0.8
=（100-0.1+11.1）×0.8+11.1
=（100+11）×0.8+11.1
=100x0.8+11x0.8+11.1
=80+8.8+11.1
=99.9