Basic basic basic, fundamental, elementary, and basic.
Please memorize this definition of acceleration:
Acceleration = (change in speed) divided by (time for the change) .
For example: Goes from 0 m/s to 10 m/s in 5.0 sec.
Change in speed = (10 - 0) = +10 m/s
Time for the change = 5.0 sec.
Acceleration = (+10 m/s) / (5.0sec) = +2 m/s² .