Brain Game: A Modern Addition
By BY

Some people will try to convince you that one is the loneliest number, that 4 for 4 is better than 1 for 1, and that 2 + 2 = 3. In what situation would the following calculations be considered correct?
9 + 5 = 2 12 + 3 = 3 10 +Â 6 = 4
Here is the SOLUTION.
THE SOLUTION:
Any base-12 system that repeats may fit this pattern (as some readers reveal in the comments); my answer deals with time.
9 + 5 = 2 Take 9 o'clock, add five hours, and it's 2 o'clock.
12 +Â 3 = 3 Take 12 o'clock, and three hours later, it's 3 o'clock.
10 +Â 6 = 4 From 10 o'clock, six hours later it would be 4 o'clock.