12.3加7.15减1.13加2.85的简便算法是什么?
问题描述:
12.3加7.15减1.13加2.85的简便算法是什么?
答
12.3+7.15-1.13+2.85
=12.3+(7.15+2.85)-1.13
=12.3+10-1.13
=22.3-1.13
=21.17