The sum of 2 numbers is 24, so let's let X equal the first number and Y equal the second number, so X + y equal 24. The first number is is traditionally means equals, but doesn't always, so be careful. The first number is 1/5 of the 2nd, so X equal 1/5 Y. What are the numbers? So if we use substitution here, instead of X + y equal 24, we're now going to put in one fifth y + y equal 24. Remembering why that is really just a number over itself. Or five fifths. So if I have 1/5 + 5 fifths, that's really 6 fifths, Y equaling 24. To get rid of the 6th fifths, I have to multiply each side by the reciprocal SO5 sixths and five sixths. So Y is going to equal 20. Now to get X, we're going to say X equaled 1/5 * y, but Y is 20, so 1/5 of 20 would be 4. So our smaller of the two numbers is 4 and our bigger of the two numbers is 20.