Let's analyze each statement:
- 17 = 17: This is true.
- 17 = 20 - 3: This is true, as 20 - 3 = 17.
- 17 + 3 = 10 + 10: This is false. 17 + 3 = 20, but 10 + 10 = 20, so this one is actually true.
- 17 + 3 = 13 + 17: This is false. 17 + 3 = 20, but 13 + 17 = 30.
The statements that are not true are:
- 17 + 3 = 13 + 17
So, the final answer is the fourth statement: 17 + 3 = 13 + 17 is NOT true.