How to subtract from positive values to negative value

[akshay6s]

I am making a summary sheet. in that sheet i am trying to subtract positive number from negative number. but that is getting summed. i have a column in which there will be both kind of numbers positive and negative. please see "summary sheet". in column J i have showed expected result.

so please give solution for this.

[TMS]

If you subtract a positive number, that makes it negative. For example, 0 - 7 = -7. And, -3 - 7 = -10. That's maths for you. In those two examples, what would you expect to see? And why?