When one quarter of a number is subtracted from one third of the number, the result is 7

The number ... n

one quarter of the number ... 1/4 of n = 1/4 * n

one third of the number ... 1/3 of n = 1/3 * n

one quarter of the number is subtracted from one third of the number ... 1/3 * n - 1/4 * n

the result is 7 ... = 7

We can put it together:

1/3 * n - 1/4 * n = 7

4/12 * n - 3/12 * n = 7

1/12 * n = 7 / * 12

n = 7 * 12

n = 84

The number you are looking for is 84.