来自孙玮的问题
8道脱式计算,3/2×5+3/5×8+3/8×11+……+3/20×23=====4/5×2/9+4/5×7/9-4/5=====48×（7/12+1/2-1)=====36×（17/18-2/9)=====53×19/52=====4/13×3/7+3/14×4/7=====9/20×399+9/20=====7/12-9/20+11/30-13/42+15/56-17/72
8道脱式计算,
3/2×5+3/5×8+3/8×11+……+3/20×23
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4/5×2/9+4/5×7/9-4/5
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48×（7/12+1/2-1)
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36×（17/18-2/9)
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53×19/52
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4/13×3/7+3/14×4/7
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9/20×399+9/20
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7/12-9/20+11/30-13/42+15/56-17/72
4回答
2020-05-15 01:58