1. 10 + 2/3 - (4+6/7)

2. 10 + 2/3 - 4 - 6/7

3. 10 - 4 + 2/3 - 6/7

4. 6 + 2/3 - 6/7

To add and subtract fractions, they must both have the same denominator. You can achieve this by multiplying the numerator and denominator by the same number.

5. 2/3 = (2 * 7)/(3 * 7) = 14/21

6. 6/7 = (6 * 3)/(7 * 3) = 18/21

7. 14/21 - 18/21 = -4/21

8. 6 + 2/3 - 6/7 = 6 - 4/21

9. = 5 + 1 - 4/21

10. = 5 + 21/21 - 4/21

11. = 5 + 17/21

Let me know if any part of that wasn't clear. Splitting 6 into 5 + 1 isn't essential (and might be confusing if introduced alongside everything else), but it makes the calculation easier.

I'll add that the name for something like "10 2/3" is "mixed number", in case you wanted to look for resources.