THE SUM OF TWO NUMBERS IS 18. THREE TIMES THE GREATER NUMBER EXCEEDS FOUR TIMES THE SMALLER NUMBER BY 5. FIND THE NUMBERS. I know the first sentence is: x + y = 18 but how do I know which number is greater and which one is smaller? If I could just set up the equation I could solve it but I don't know how to set the equation up. You are right with your first equation, x + y = 18 You asked "how do I know which number is greater and which one is smaller". The answer is, you don't. You assume the larger number to be x or vice versa or the larger number to be y and vice versa. Algebra is very flexible and you will get the right answer both ways. Your second sentence is: THREE TIMES THE GREATER NUMBER EXCEEDS FOUR TIMES THE SMALLER NUMBER BY 5. FIND THE NUMBERS Let's assume the greater number to be x and the smaller number to be y. Hence we get, 3x = 4y + 5 We now have a pair of simultaneous equations! x + y = 18...(1) 3x = 4y + 5...(2) Manipulate (1): Make x the subject of the equation --- x = 18 - y...(3) Substitute (3) into (2): 3(18-y) = 4y + 5 54 - 3y = 4y + 5 7y = 49 y = 7...(4) Substitute (4) into (3) x = 18 - 7 = 11 Our two numbers are 11 and 7!