What is 9 + 10 =
19
What is 10 - 5 =
5
What is 5 - 1 =
4
What is 4 - 1 =
3
What is 1 - 1 =
0
What is 666 - 100 =
566
What is 6 - 2 =
What is 8 + 1 =
7
2