7/13×4/5+6/13÷4/5 （7/24－3/16)÷1/8 7/13×4/5+6/13÷5/4简便运算 /是分数线

题目

7/13×4/5+6/13÷4/5 （7/24－3/16)÷1/8 7/13×4/5+6/13÷5/4简便运算 /是分数线
我打错了.还有一个是（3/5+1/3)x15

答案

7/13×4/5+6/13÷4/5
=7/13*4/5+6/13*5/4
=2/13*(14/5+15/4)
=2/13*(14*4+15*5)/20
=2*(56+75)/13*20
=262/260
=131/130
（7/24－3/16)÷1/8
=(7/24-3/16)*8
=7/3-3/2
=14/6-9/6
=5/6
7/13×4/5+6/13÷5/4
=7/13*4/5+6/13*4/5
=4/5*(7/13+6/13)
=4/5*1
=4/5