31.7x0.9+3.17 和 2.5x4.6+0.25x46 怎么简算?

31.7x0.9+3.17 和 2.5x4.6+0.25x46 怎么简算?
31.7x0.9+3.17 和 2.5x4.6+0.25x46 怎么简算?

31.7x0.9+3.17 和 2.5x4.6+0.25x46 怎么简算?
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

31.7（0.9+0.1）=31.7
第二个路过

31.7x0.9+3.17=3.17x10x0.9+3.17x1
=3.17x9+3.17x1
=3.17x（9+1）
=31.7
2.5x4.6+0.25x46 =2.5x4.6+0.25x10x4.6
...

全部展开

31.7x0.9+3.17=3.17x10x0.9+3.17x1
=3.17x9+3.17x1
=3.17x（9+1）
=31.7
2.5x4.6+0.25x46 =2.5x4.6+0.25x10x4.6
=2.5x4.6+2.5x4.6
=2x2.5x4.6
=5x4.6
=23

收起

31.7*（0.9+0.1） 4.6（2.5+2.5）