Question

简便计算：

Answer 1

1又1/4+2又1/28+3又1/70+4又1/130
=(1+2+3+4)+(1/4+1/28+1/70+1/130)
=10+(7/28+1/28+1/70+1/130)
=10+(8/28+1/70+1/130)
=10+(2/7+1/70+1/130)
=10+(20/70+1/70+1/130)
=10+(21/70+1/130)
=10+(3/10+1/130)
=10+(39/130+1/130)
=10+(40/130)
=10+4/13
=10又4/13

Answer 2

1/3(1-1/4+1/4-1/7+……+1/16-1/19）+2+4+6+8+10
=1/3（1-1/19）+30
=30又6/19

追答

这题原来做过比你这题多几个数，
方法是：
1/(1*4)=1/3*(1-1/4)
1/(4*7)=1/3*(1/4-1/7)
以此类推
然后将1/3提取出来的