Match the top cards to the bottom cards to show doubles plus 1

This question is all about doubles. The given bottom cards 5 2 3 4 and the top cards are 1 4 3 2.

The problem is asking to match the top cards to the bottom ones then adding 1 to get the doubles.

So 1 should be corresponding to two. Since 1 + 1 = 2

4 should be corresponding to 5. Since 4 + 1 = 5

3 should be corresponding to 4. Since 3 + 1 = 4

And lastly, 2 should be corresponding to 3. Since 2 + 1 = 3