This is the 14857th most frequent Russian word.
повторения
Repetitions.
The term "повторение" means "repetition" and is used in a general sense, indicating the act of revisiting or reviewing something.
Повторение материала укрепляет знания.
Repetition of material strengthens knowledge.
Here, "повторений" refers to specific instances of repeating an action, in this case doing exercise repetitions.
Учитель попросил сделать несколько повторений упражнения.
The teacher asked to do several repetitions of the exercise.
In this sentence, "повторения" denotes the action of committing the same errors again, emphasizing a warning or advice.