8.4+3.5-8.4+3.5脱式计算.

问题描述:

8.4+3.5-8.4+3.5脱式计算.

8.4+3.5-8.4+3.5
=(8.4-8.4)+3.5+3.5
=0+3.5+3.5
=3.5+3.5
=7