Question

1/3+1/6+1/10+1/15+1/21+1/28+1/36+1/45=几？

Answer 1

1/岩肆拦3+1/6+1/10+1/15+1/21+1/28+1/粗胡36+1/45
=(1/3+1/6)+(1/10+1/15)+(1/21+1/28)+(1/36+1/45)
=(2+1)/6+(3+2)/30+(4+3)/84+(5+4)/180
=1/2+1/6+1/12+1/20
=1/2+(1/雹雀2-1/3)+(1/3-1/4)+(1/4-1/5)
=1-1/5
=4/5

Answer 2

怎么又出现一次啊。
思路：你可以观察分母，它的相邻两分母之差可以组成一个段迟等差数列，有了这一个数列的方程在解原握带李列的前行升十八项之和还不容易吗?

Answer 3

1/3+(1/2-1/3)+(1/2-1/5)/3+1/15+(1/3-1/基销7)/4+1/28+(1/4-1/9)/5+1/45
=1/2+1/6+1/12+1/20
=1/2+1/2-1/3+1/3-1/4+1/4-1/搏灶游辩孝5
=4/5

Answer 4

4/5