If the number of students increased by 20%, then the total number of students this year is 100% + 20% = 120% of the number of students last year.
Let's represent the number of students last year as 'x'.
So, 120% of 'x' is equal to 960.
120% of 'x' can be written as (120/100) * 'x'.
So, (120/100) * 'x' = 960.
Simplifying the equation, we get 1.2 * 'x' = 960.
Dividing both sides by 1.2, we get 'x' = 800.
Therefore, there were 800 students last year.
#### 800
The answer is: 800
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
In my school, the number of students has increased by 20% this year. The number of students this year is 960. How many students were there last year?

### Answer:
