a number is divided by 6.Then 7 is added to the divisor. after dividingby, thye result is 4. what is the number

Did you mean 7 is added to the result after dividing by 6 ?

Else how can you add 7 to the divisor if the division has been done?

The wording is very odd.

According to my interpretation:

x/6 + 7 = 4
x/6 = -3
x = -18