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1.2×与9.7+0.3×与1.2想怎么简便就怎么简便

4.86×9.7+0.486×3 =4.86x9.7+4.86x0.3 =4.86x(9.7+0.3) =4.86x10 =48.6 得到的结果为48.6 如果是4.86×9.7×0.486×3就没有简便方法,可以使用计算器算比较容易。

3个数算一个循环,等于0+0.3+0.6+...+9.6=0.3(1+2+...+32)=0.3*(1+32)*32/2

9.9+9.8+9.7+0.6=(9.9+0.1)+(9.8+0.2)+(9.7+0.3)=10+10+10=30

10×50=500, 180÷2=90, 5-2.1=2.9, 70×70=4900, 4200÷7=600, 9.7+0.3=10, 13×20=260, 450÷5=90, 21×30≈600, 48×29≈1500, 207÷5≈40, 290÷9≈30.故答案为:500,90,2.9,4900,600,10,260,90,600,1500,40,30.

13-3.79+9.7-6.2 =13+10-0.3-(3.79+6.2) =23-0.3-9.99 =23-10-0.3-0.01 =13-0.31 =12.69

=3.26✘(4.5+5.2)+(10-0.3)✘6.74 =3.26✘10+10✘6.74-0.3✘6.74 =10✘(3.26+6.74)-2.022 =10✘10-2.022 =100-2.022 =97.978

0.1+0.2+0.3+0.4+…+9.7+9.8=0.1+(0.2+9.8)×97÷2 =0.1+10×97÷2 =0.1+970÷2 =0.1+485 =485.1 5.0+5.1+5.2+5.3+…9.9+10.0=(5.0+10.0)×51÷2 =15×51÷2 =382.5

解: 如果是4.7×0.3+0.47×9.7的简算 =4.7x0.3+4.7x0.97 =4.7x(0.3+0.97) =4.7x1.27 =1.27x4+1.27x0.7 =5.08+0.889 =5.969

0.1+0.2+0.3+0.4+……+9.8+9.9 =(0.1+9.9)*99/2 =5*99 =495 0.1+0.3+0.5+0.7……+9.7+9.9 =(0.1+9.9)*50/2 =...

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