On the first play of the game a running back gained 7 yards. on the next play he lost 19 yards find the change in yards i'm the 2 plays

The question isn't the best worded so i'm making a lot of assumptions here:

First play: gained 7 yards

Second play: lost 19 yards

Find the change in yards.

The question is asking what is the change to make + 7 into - 19.

You can do this however you like, i. e. in your head

If you cannot do it in your head I suggest you use the rule:

[Larger Number] - [Smaller Number]

to find the difference/change

+7 - - 19 (to negatives make a positive rule)

= + 7 + 19

= + 26

The answer is + 26 change in yards