When the sum of 6 and a number is divided by -2, the result is 5.

     Put parentheses around (a number)

When the sum of 6 and (a number) is divided by -2, the result is 5.

     Put N in place of (a number)

When the sum of 6 and N is divided by -2, the result is 5.

     Put parentheses around (the sum of 6 and N)

When (the sum of 6 and N) is divided by -2, the result is 5.

     Put (6+N) in place of (the sum of 6 and N)

When (6+N) is divided by -2, the result is 5.

     Put parentheses around -2

When (6+N) is divided by (-2), the result is 5.

     Put parentheses around (is divided by)

When (6+N) (is divided by) (-2), the result is 5. 

     Put / in place of (is divided by)

When (6+N)/(-2), the result is 5.

     Put parentheses around (the result is)

When (6+N)/(-2), (the result is) 5.

     Put = in place of (the result is)

When (6+N)/(-2), = 5.

     Erase the 'When', the comma and the period:

(6+N)/(-2) = 5

     Now you finish.

Edwin