Question

1.1+2.3+3.5+4.7+5.9+6.2+7.4+8.6+9.8怎么简便？

Answer 1

简便的原则就是 凑整
末尾相加凑整就可以了
（1.1+5.9）+（2.3+4.7）+（7.4+8.6）+（6.2+9.8）+3.5

Answer 2

简便运算如下
(1.1+5.9)+（2.3+4.7）+（6.2+9.8）+（7.4+8.6）+3.5
=7+7+16+16+3.5
=14+32+3.5
=49.5

Answer 3

解
1.1+2.3+3.5+4.7+5.9+6.2+7.4+8.6+9.8
=（1.1+9.8）+（2.3+8.6）+（3.5+7.4）+（4.7+6.2）+5.9
=10.8+10.8+10.8+10.8+5.9
=10.8×4+5.9
=49.1

Answer 4

1.1+2.3+3.5+4.7+5.9+6.2+7.4+8.6+9.8
=1.1+5.9+2.3+4.7+6.2+9.8+7.4+8.6+3.5
=7+7+16+16+3.5
=14+32+3.5
=46+3.5
=49.5。

Answer 5

1.1+2.3+3.5+4.7+5.9+6.2+7.4+8.6+9.8
=1+0.1+2+0.3+3+0.5+。。。+9+0.8
=1+2+3+。。。+9+0.1+0.2+。。。0.9
=（1+9）*9/2+（0.1+0.9）*9/2
=45+4.5
=49.5