The sum of a three-digit number and a one-digit number is 160. the product of the two numbers is 624. what are the two numbers?

Let's look at all the potential numbers: 
3-Digit Numbers: 151, 152, 153, 154, 155, 156, 157, 158, 1591-Digit Numbers: 9, 8, 7, 6, 5, 4, 3, 2, 1
See what numbers the product is divisible by via either a calculator or long division. (Divisible means that when you divide it by said number it comes out as a whole number. Example 624/1 = 624) Once you've done that for the 1 digit numbers, also do the same process for the 3 digit numbers. 
Divisible 1-Digit Numbers: 8, 6, 4, 3, 2, 1Divisible 3-Digit Numbers: 156
The 3-Digit Number has to be 156. So the complimentary number with it is 4. (Because 160-156 = 4) 
So our answers are: 156, and 4