7/10+3/8-2/5脱式计算简便方法？
7/10+3/8-2/5
=7/10-2/5+3/8
=7/10-4/10+3/8
=3/10+3/8
=12/40+15/40
=27/40
原式=7/10-2/5+3/8=7/10-4/10+3/8=3/10+3/8=12/40+15/40=27/40希望能帮到你
=7/10-4/10+3/8=3/10+3/8=12/40+15/40=27/40
