Breakdown of Я занимаюсь математикой вечером.
Questions & Answers about Я занимаюсь математикой вечером.
The ending -сь (or -ся in the infinitive заниматься) marks a reflexive verb in Russian.
- The base verb is занимать – to occupy (something).
- заниматься literally means to occupy oneself with something, so it doesn’t take a direct object in the accusative.
- Instead, it uses the instrumental case to show what you are occupied with.
So я занимаюсь математикой means roughly I occupy myself with math / I am engaged in math, which is understood as I study math / I do math.