on the first play of a game , a football team gained 23 yards and then lost 10 yards due to penalty during the second play the team gained 8 yards, on the third and fourth play the team lost 11 yards in each play? how many yards in total did the tram gain or lose during the four plays?

-1 Let's say the set of downs starts at the 20 yard line (maybe the kicking team kicked deep, the receiving team took a knee and so play starts at the 20).
Ok - we're at the 20. First down - they advance 5 yards. So we're now at the 25. We can write that mathematically as:
20
+
5
=
25
So the second play they get sacked deep and lose 6 yards. So we subtract 6:
25
−
6
=
19
So what's the change in yardage for the 2 plays? We are on the 19 and started at the 20, so we can write:
19
−
20
=
−
1
and this makes sense because we know we advanced 5 and fell back 6