31.7x0.9+3.17 和 2.5x4.6+0.25x46 怎么简算?
问题描述：
31.7x0.9+3.17 和 2.5x4.6+0.25x46 怎么简算?
答
31.7×0.9+3.17
=3.17×9+3.17
=3.17×（9+1）
=3.17×10
=31.7
2.5×4.6+0.25×46
=2.5×4.6+2.5×4.6
=4.6×（2.5+2.5）
=4.6×5
=23
亲这个就是用1×100会等于10×10一样的道理