The difference between two numbers is 56. Five times the smaller is equal to 4 more than the larger. What are the numbers?

The numbers are 71 and 15.

Explanation:
Let x = the first number
Let y = the second number

From what they give us, we know:
x - y = 56
5y = x + 4

Either one of the equations can be rearranged and substituted into the other equation to find one variable, or number.

5y = x + 4
5y - 4 = x or x = 5y - 4

x - y = 56
5y - 4 - y = 56
4y - 4 = 56
4y = 60
y = 15

To find the other variable (number), substitute that value in either equation.

x - y = 56
x - 15 = 56
x = 71

To check the solutions, substitute both variables into each equation to make sure they work.

x - y = 56
71 - 15 = 56
56 = 56

5y = x + 4
5*15 = 71 + 4
75 = 75