31.7x0.9+3.17 和 2.5x4.6+0.25x46 怎么简算?

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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)