you're counting on your fingers, but you're only using for fingers, so it goes like this
IIII (four fingers) IIII (new hand) III (total = 11) then you add two to make it go IIII (four fingers) and the second of the two makes it I (one finger)
Either that, or you're a complete dunce and don't know how to count.
Alright. If you arrange it in Roman Numerals with tooth picks, since you're 'adding' them together, you use a plus stick for a one in the three, and rearrange the X to a V, then move the one toothpick beside the l over, you get 4 - 3 = 1. HA!