1.)
Velocity is in m/s, and acceleration is in m/s^2 like you said. Because of this, we can calculate this by dividing the speed by the time it took to get to that speed.
(20 meters/second) / 10 seconds = 2 meters/ second^2
2.)
Same thing with the first one.
(100 meters/second) / 4 seconds = 25 meters / seconds^2
The answer is 5 because if you add 10 to -10 it is 0 then add the 5 more and it is 5.
