100%=$1...

My two boys, Isaac and Caleb get a dollar for any 100% they get on a math lesson. I correct their lesson in anticipation as I sometimes get up to number 12, 13 or 16 even without one wrong (total of 25 problems usually) and then bam, 1, 2, 3 or more wrong in the last half and I'm a little deflated waiting and hoping for it to happen. Today, it happened. I corrected Caleb's lesson from yesterday and he got 100%! He was yelling down the hallway letting everyone know he gets a dollar. He only has 32 lessons left of the year, only 32 more chances to get another dollar. We'll see how many more he can get!?!