Two two-digit numbers

1. Add Board: 13 + 12
2. Add Board: 20 + 20
3. Number detectives: 51+11 = ?
4. Word Wise!: 19 less than 19
5. 100 grid: 88 take away 11
6. 100 grid: 11 take away 11
7. 100 grid: 23 take away 11
8. 100 grid: 64 take away 11
9. 100 grid: 73 take away 11
10. 100 grid: 99 take away 11
11. Number detectives: 30 - 14 = ?