The two numbers are 4 and 5. So 4×5=20 and 5+4=9. The answer is 9 and 20.

You can also use the formula a x b = c, where a is the first number, b is the second number, and c is the outcome of multiplying them together. In this case you’d use 4×5=20, so 20=c. Then you’d simply subtract 5 from both sides of your equation to get c-5=20-5, which gives you c-5=-15. Now all you have to do is divide both sides by -1: 15/1=-15/15=1/15=-7/15=-0.3678***

In this example, I’ve used an algebraic approach to solve the problem because it’s just so much easier than trying to work out what two numbers multiply to 20 and add up to 9 by hand (which would be pretty hard). But there’s another way we could have solved this problem — by using a combination of logic and mathematics.

Last modified: August 7, 2022