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运算定律与 简算的整理

运算定律与 简算的整理. 找一找：谁和谁是好朋友？. 72. 51. 178. 125. 25. 263. 28. 163. 49. 8. 22. 4. 想一想，横线上应该填什么会使计算更加简便？你是怎么想的？. 25×137×. 4. 125×61×. 8. 练习一：简便计算. 107+158+93+42 487-139-61 （125+40）×8 25×44 3200÷25÷4 66×101-66.

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运算定律与 简算的整理

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  1. 运算定律与 简算的整理

  2. 找一找：谁和谁是好朋友？ 72 51 178 125 25 263 28 163 49 8 22 4

  3. 想一想，横线上应该填什么会使计算更加简便？你是怎么想的？想一想，横线上应该填什么会使计算更加简便？你是怎么想的？ 25×137× 4 125×61× 8

  4. 练习一：简便计算 107+158+93+42 487-139-61 （125+40）×8 25×44 3200÷25÷4 66×101-66 同桌之间相互交流一下，每道题分别运用了什么运算定律？

  5. 练习二： 25×444 25×444 =25×（400+40+4） =10000+1000+100 =11100 =25×4×111 =100×111 =11100

  6. 练习三：改错 8×50×2×125 =8×125+50×2 =1000+100 =1100 8×50×2×125 =(8×125)×(50×2) =1000×100 =100000

  7. 102×89 =（100+2）×89 =89×100+2 =8902 102×89 =（100+2）×89 =89×100+2×89 =8900+178 =9078

  8. 练习四： 李大爷家有一块菜地（如下图），这块菜地的面积有多少平方米？ 8米 21米 19米 8米

  9. 思考： 小明在计算（□+50）×4时，算成 □×4+50，他的计算结果和正确结果相比，怎么样？

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