北师大四年级数学下册小数乘法简便计算(最新整理)

四年级下册小数练习题

一、脱式计算，能简算的要简算。

7.8×1.3+0.948-1.8×240.25×0.46×0.4

2.5×1.3+0.9

3.8×41-3.8（4+0.4）×2.5

0.27×3.8+0.27×6.22.9×100.127.5×101-27.5

40×0.63×0.253.62×25.7+3.62×74.30.25×4.87×4

18.8+23.6+26.410.95-3.74-4.2695.59-（9.59+12.78）

25.6-(0.23+5.6)-1.7713.75-(4.75+6.48)7.83+2.34-0.83+6.66 3.82+2.9+0.18+9.15.93+0.19+2.8125.48-((9.4-0.52)3.07-0.38-1.6235.6-1.8-15.6-7.27.3+2.7-7.3+2.748.4+2.78+51.6-0.78 23.4+0.8-13.4-7.24.8+8.63+5.2+0.373.25+2.76+1.75 1.27+3.9+0.73+15.15.84-1.8-3.2132.44-(58.74+19.44) 7.5+4.8-6.5

7.14-0.53-2.4713.75-(3.75+6.48)13.45-4.68+2.5547.8-7.45+8.2 36.8-4.5+6.9849.8-9.6+8.815.2-6.8-3.451.76+0.65+3.24

0.134+2.66+0.87.5+4.9-6.33.45+1.79+0.654.85+8.63+0.37

1.76+3.44+0.3536.54-1.76-8.668-

2.45-1.022

3.4+3.4-0.23 6.02+3.6+1.983.07-0.38-1.627.5+

4.9-6.536.8-3.9-6.883.285+1.79+0.5923.4-0.8+13.432+4.9-8.6 1.29+3.7+2.71

5.93+0.49+2.069-2.45-1.65 21+0.56+11.364.89-7.88-13.6

二、能简便的要简便计算。

12.5×8.2×80.23×1.4＋0.23×8.6

0.125×（80＋0.8）0.4×0.16×2.5

5.6×1017.85×991.15×99＋1.15

16.2×101－16.245×0.78＋5.5×7.8

2.8+7.2×0.810.34×2.5×0.41.25×11×4×0.8

8.93×5.7＋8.93×3.3＋8.934.82×102

0.7×0.46+0.7×0.545.6-4.34+7.34685.7-（15.3-4.8）

25.4-（15.3+7.7）3.6－1.28＋3.093.8-0.46-1.723

25.6-(0.23+5.6)-1.7713.75-(4.75+6.48)7.83+2.34-0.83+6.663.82+2.9+0.18+9.1

25.48-((9.4-0.52)35.6-1.8-15.6-7.25.93+0.19+2.81

7.3+2.7-7.3+2.73+5.2+0.373.07-0.38-1.62

48.4+2.78+51.6-0.7823.4+0.8-13.4-7.24.8+8.6

1.27+3.9+0.73+15.15.84-1.8-3.213

2.44-(58.74+19.44)7.5+4.8-6.51

3.45-

4.68+2.55

3.25+2.76+1.7513.75-(3.75+6.48)7.14-0.53-2.47

47.8-7.45+8.236.8-4.5+6.9849.8-9.6+8.8

15.2-6.8-3.453.45+1.79+0.653.45+1.79+0.65

1.76+0.65+3.240.134+

2.66+0.87.5+4.9-6.34.85+8.63+0.371.76+

3.44+0.3536.54-1.76-8.66

3.45+1.79+0.657.5+

4.9-6.5

23.4+3.4-0.236.02+3.6+1.983.07-0.38-1.62

36.8-3.9-6.883.285+1.79+0.5923.4-0.8+13.4

1.29+3.7+

2.7121+0.56+11.332+4.9-8.65.93+0.49+2.069-2.45-

1.65

一、乘法交换律

a ⨯

b ⨯

c =a ⨯c ⨯b

0.25×8.5×412.5×0.96×0.80.25×0.73×40.25×16.2×4

二乘法结合律

（a⨯b）⨯c=a⨯（c⨯b）

4.36×12.5×80.95×0.25×435×0.2×0.50.75×50×0.4

三、乘法分配律

(a ± b)⨯c =a ⨯c ±b ⨯c

(1.25－0.125)×8（20－4）×0.25(2+0.4)×5（125+2.5）×0.8

四、乘法分配律逆应用

a ⨯

b ± a ⨯c=a(b ±c)

3.72×3.5＋6.28×3.515.6×2.1－15.6×1.1 3.83×

4.56＋3.83×

5.44 7.09×10.8－0.8×7.0927.5×3.7－7.5×3.7 3.9×2.7＋3.9×7.3

10.6×0.35－9.6×0.357.6×0.8＋0.2×7.6

五、把其中一个因数分成两个数的和或差，再按乘法分配律

0.8×100.10.79×990.85×199 3.65×10.1

4.6×0.90.65×101 4.8×10.1 3.6×102

0.39×1998.9×1.010.32×403 3.65×10.1

0.85×9.90.65×101

六、拆分因数

1.25×

2.5×32

3.2×0.25×12.50.25×3625×

4.48.8×1.25

七、添加因数“1”

56.5×99＋56.5 9.7×99＋9.7 4.2×99＋4.2 5.4×11-5.4