计算下面各题,好的80分好的80分!

计算下面各题,好的80分好的80分!
计算下面各题,好的80分


好的80分!

计算下面各题,好的80分好的80分!
1.原式=1/5（101-21）=1/5*80=16
　　2.原式=5.8*3.74+4.2*3.74=3.74（5.8+4.2）=3.74*10=37.4
　　3.原式=1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10=1/5-1/10=1/10
　　4.原式=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7=1/2-1/7=5/14
　　5.原式=9/7-2/7+10/21=1+10/21=31/21.

101*1/5-1/5*21
=(101-21)*1/5
=80*1/5
=16
5.8*(3.87-0.13)+4.2*3.74
=5.8*3.74+4.2*3.74
=(5.8+4.2)*3.74
=10*3.74
=37.4
1/30+1/42+1/56+1/72+1/90
=1/5-1/6+1/6-1/7+1/...

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101*1/5-1/5*21
=(101-21)*1/5
=80*1/5
=16
5.8*(3.87-0.13)+4.2*3.74
=5.8*3.74+4.2*3.74
=(5.8+4.2)*3.74
=10*3.74
=37.4
1/30+1/42+1/56+1/72+1/90
=1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1/5-1/10
=1/10
1/6+1/12+1/20+1/30+1/42
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1/2-1/7
=5/14
9/7-(2/7-10/21)
=9/7-2/7+10/21
=1+10/21
=1又21分之10

收起

1、提取1/5，得到1/5*（101-21）=1/5*80=16
2、提取3.74，得到3.74*（5.8+4.2）=37.4，注意3.87-0.13=3.74
3、因为1/30=1/5-1/6，1/42=1/6-1/7，所以，最后等于1/5-1/10=1/10
4、同第三题的道理，得到1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7=1/2-...

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1、提取1/5，得到1/5*（101-21）=1/5*80=16
2、提取3.74，得到3.74*（5.8+4.2）=37.4，注意3.87-0.13=3.74
3、因为1/30=1/5-1/6，1/42=1/6-1/7，所以，最后等于1/5-1/10=1/10
4、同第三题的道理，得到1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7=1/2-1/7=5/14
5、9/7-（6/21-10/21）=27/21-6/21+10/21=31/21

收起

1、101×1/5-1/5×21
=（101-21）×1/5
=80×1/5
=16
2、5.8×（3.87-0.13）+4.2×3.74
=5.8×3.74+4.2×3.74
=（5.8+4.2）×3.74
=10×3.74
=37.4
3、1/30+1/42+1/56+1/72+1/90
=1/5-1/6+1/6-...

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1、101×1/5-1/5×21
=（101-21）×1/5
=80×1/5
=16
2、5.8×（3.87-0.13）+4.2×3.74
=5.8×3.74+4.2×3.74
=（5.8+4.2）×3.74
=10×3.74
=37.4
3、1/30+1/42+1/56+1/72+1/90
=1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9+1/9-1/10
=1/5-1/10
=1/10
4、1/6+1/12+1/20+1/30+1/42
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7
=1/2-1/7
=5/14
5、9/7-（2/7-10/21）
=9/7-2/7+10/21
=1+10/21
=1又10/21

收起

1）=（101-21）/5=80/5=16
2）=5.8×3.74+4.2×3.74=（5.8+4.2）×3.74=10×3.74=37.4
3）=3/90+4/168+3/168+1/72+1/90
=4/90+7/168+1/72
=4/90+1/24+1/72
=4/90+3/72+1/72
=4/90+1/18=4/90+5/90=9/90<...

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1）=（101-21）/5=80/5=16
2）=5.8×3.74+4.2×3.74=（5.8+4.2）×3.74=10×3.74=37.4
3）=3/90+4/168+3/168+1/72+1/90
=4/90+7/168+1/72
=4/90+1/24+1/72
=4/90+3/72+1/72
=4/90+1/18=4/90+5/90=9/90
=1/10
4）=2/12+1/12+1/20+1/30+1/42
=1/4+1/20+1/30+1/42
=3/10+1/30+1/42
=1/3+1/42
=15/42
=5/14
5）=9/7-（6/21-10/21）
=9/7+4/21
=27/21+4/21
=31/21

收起

101X1/5-1/5X21
=1/5x(101-21)
=1/5X80
=16
5.8X(3.87-0.13)+4.2X3.74
=5.8X3.74+4.2X3.74
=3.74X(5.8+4.2)
=3.74X10
=37.4
1/30+1/40+1/56+1/72+1/90
=1/6X1/5+1/8X1/5+1/...

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101X1/5-1/5X21
=1/5x(101-21)
=1/5X80
=16
5.8X(3.87-0.13)+4.2X3.74
=5.8X3.74+4.2X3.74
=3.74X(5.8+4.2)
=3.74X10
=37.4
1/30+1/40+1/56+1/72+1/90
=1/6X1/5+1/8X1/5+1/7X1/8+1/8X1/9+1/18X1/5
=1/5X(1/6+1/8+1/18)+1/8X(1/7+1/9)
=5/72+2/63
=5/8X1/9+2/7x1/9
=1/9x(5/8+2/7)
=1/9x(35/56+16/56)
=1/9x51/56
17/168
1/6+1/12+1/20+1/30+1/42
=1/6+1/2X1/6+1/4x1/5+1/6x1/5+1/6x1/7
=1/6x(1+1/2+1/5+1/7)+1/20
=1/6x(70/70+35/70+14/70+10/70)+1/20
=1/6x129/70+1/20
=43/140+1/20
=43/7x1/20+1/20
=(43/7+1)x1/20
=50/7x1/20
=5/14
7/9-(2/7-10/21)
=7/9-2/7+2/7x5/3
=7/9+2/7(5/3-1)
=7/9+4/21
=7/3x1/3+1/3x4/7
=1/3x(7/3+4/7)
=1/3x(49/21+12/21)
=1/3x51/21
=17/21

收起