Answer :
The sum of a number and 5, less than 10, is 3 can be expressed as:
x + 5 - 10 = 3
where x is unknown number.
x + 5 = 3 + 10
x + 5 = 13
x = 13 - 5
x = 8
x + 5 - 10 = 3
where x is unknown number.
x + 5 = 3 + 10
x + 5 = 13
x = 13 - 5
x = 8