作业帮小数运算的速算和简算,1.2121212÷3.303033.3+3.33+3.333+3.3333+3.333331990×198.9-1989×198.860.7×0.60.45×172-0.9×71×0.5-0.45简算不是直接计算，这样我老早就直接用计算机算了
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小数运算的速算和简算,1.2121212÷3.303033.3+3.33+3.333+3.3333+3.333331990×198.9-1989×198.860.7×0.60.45×172-0.9×71×0.5-0.45简算不是直接计算，这样我老早就直接用计算机算了
小数运算的速算和简算,
1.2121212÷3.30303
3.3+3.33+3.333+3.3333+3.33333
1990×198.9-1989×198.8
60.7×0.6
0.45×172-0.9×71×0.5-0.45
简算不是直接计算，这样我老早就直接用计算机算了
小数运算的速算和简算,1.2121212÷3.303033.3+3.33+3.333+3.3333+3.333331990×198.9-1989×198.860.7×0.60.45×172-0.9×71×0.5-0.45简算不是直接计算，这样我老早就直接用计算机算了
1.2121212÷3.030303(怀疑此题抄丢一个零,故加上一个零)
=1.2*1.010101/3*1.010101
=0.4
3.3+3.33+3.333+3.3333+3.33333
=3*1.1+3*1.11+3*1.111+3*1.1111+3*1.11111
=3*(1.1+1.11+1.111+1.1111+1.11111)
=3*5.5432
1990×198.9-1989×198.8
=1990×198.9-(1990×198.8-198.8)
=1990×198.9-1990×198.8+198.8
=1990×(198.9-198.8)+198.8
=1990*0.1+198.8
=199+198.8
60.7×0.6
=(60+0.7)*0.6
=36+0.42
=36.42
0.45×172-0.9×71×0.5-0.45
=0.45×172-0.45×71-0.45
=0.45*(172-71-1)
=0.45*100
=45
用键盘写算式太费劲.有的题没计算到最后,计算到最后的答案也未必对.只是方法和思路应该是正确的.时间匆匆,有不准确的地方,见谅!
1.2121212÷3.30303=0.3669725
3.3+3.33+3.333+3.3333+3.33333
=6.63+6.6663+3.33333
=13.2963+3.33333
=12.62963
1990×198.9-1989×198.8
=395811-395413.2
=397.8
60.7×0.6
=36.42
0.45×172-0.9×71×0.5-0.45
=77.4-31.95-0.45
=45
估计第一题掉了个零
1.2121212÷3.030303=3*0.4040404÷（3*1.010101）
=0.4
3（1.1+1.11+1.111+1.1111+1.11111）=3*5.54321
=16.62963
1990×198.9-1989...
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估计第一题掉了个零
1.2121212÷3.030303=3*0.4040404÷（3*1.010101）
=0.4
3（1.1+1.11+1.111+1.1111+1.11111）=3*5.54321
=16.62963
1990×198.9-1989×198.8
=199*1989-198.8*1989
=（199-198.8）*1989
=0.2*1989
=397.8
60.7×0.6
=（60+0.7）*0.6
=36+0.42
=36.42
0.45×172-0.9×71×0.5-0.45
=0.45*172-0.45*71-0.45
=0.45*（172-71-1）
=0.45*100
=45
基本就是这样 希望可以对你有用
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