eli5 why do we “forget” long practiced skills after a period of time of not using said skills? and how can we regain those skills

Question

i noticed that after the holidays my math plummeted and teachers told me its because of the break i took… why does this happen and how can i regain those skills acquired prior to the break

In: 356

Answer 1

All these answers are too complicated.
ELY5:
Practice makes perfect.
No practice, no perfect.