Match the numbers. 16-3, 38-4, 17-4, 23-7, 14-2, 24-9, 20-6, 21-8

Here are the calculations for each pair of numbers:

1. For 16 and 3: Sum: $16 + 3 = 19$ Difference: $16 - 3 = 13$ The numbers are $\boxed{19 and 13}$.

2. For 14 and 2: Sum: $14 + 2 = 16$ Difference: $14 - 2 = 12$ The numbers are $\boxed{16 and 12}$.

3. For 38 and 4: Sum: $38 + 4 = 42$ Difference: $38 - 4 = 34$ The numbers are $\boxed{42 and 34}$.

4. For 24 and 9: Sum: $24 + 9 = 33$ Difference: $24 - 9 = 15$ The numbers are $\boxed{33 and 15}$.

5. For 17 and 4: Sum: $17 + 4 = 21$ Difference: $17 - 4 = 13$ The numbers are $\boxed{21 and 13}$.

6. For 20 and 6: Sum: $20 + 6 = 26$ Difference: $20 - 6 = 14$ The numbers are $\boxed{26 and 14}$.

7. For 23 and 7: Sum: $23 + 7 = 30$ Difference: $23 - 7 = 16$ The numbers are $\boxed{30 and 16}$.

8. For 21 and 8: Sum: $21 + 8 = 29$ Difference: $21 - 8 = 13$ The numbers are $\boxed{29 and 13}$.