I want to show you two ways to approach this problem, one using algebra and the other using number sense. I expect that your teacher expects the algebraic approach but I prefer the number sense method.
- Algebraic method.
- Suppose that the smaller of the two numbers is $s.$ The second number is 2 more then $s$ so the second number is $s + 2.$ The sum of the two numbers is 4. Write this as an equation and solve for $s.$ Make sure you verify your answer.
- Number Sense method.
- Suppose the question was "The difference of two numbers is 0, and their sum is 4. What are the numbers?" In this case the numbers are $2$ and $2.$ But you want the difference between the two numbers to be $2.$ If you increase one of the two's by one to get $3$ and decrease the other by one to get $1$ then their sum will still be $4$ but their difference will be $2.$
I hope this helps,