7/13×5/8+2/13×7/16-1/13×3又1/2

题目

7/13×5/8+2/13×7/16-1/13×3又1/2

答案

7/13×5/8+2/13×7/16-1/13×3又1/2
=1/13 x(7*5/8+2*7/16-7/2)
=1/13 *(70/16+14/16-56/16)
=1/13 *28/16
=1/13* 7/4
=7/52