七分之三加七分之四减八分之五

Answer 1

4/7-3/8+5/7+3/8 =4/7+5/7+3/8-3/8 =9/7 =1又2/7

Answer 2

(1)3/7+4/7-5/8
=1-5/8
=3/8
(2)3/7+(4/7-5/8)
=3/7+(32/56-35/56)
=3/7-3/56
=24/56-3/56
=21/56
=3/8

Answer 3

3/7+4/7-5/8
=1-5/8
=8/8-5/8
=3/8