Answer:
1. 7 or S
2. 2 or E
3. 5 or A
4. 3 or I
5. 9 or the shaded-in letter
6. 11 or T
7. 20 or E
Explanation:
1. 7 times 2 is 14, and 7 times 3 is 21
2. 2 times 5 is 10, and 2 times 6 is 12
3. 5 times 3 is 15, and 5 times 5 is 25
4. 3 times 2 is 6, and 3 times 5 is 15
5. 9 times 4 is 36, and 9 times 3 is 27
6. 11 times 2 is 22, and 11 times 3 is 33
7. 20 times 3 is 60, and 20 times 1 is 20.