My son has the following missing number pattern to solve.

? 17 37

29 38 9

1 21?

I can not figure this out. What is the answer for the questions marks?

The only complete pattern is the middle one

we see that 38-29=9

so the middle number minus the first number equals the third number

for the last row

21-1=20 so you have 1 21 20

for the first one

17 - ?=37

54-17=37 54 17 37

For the first one is 1,21,20

The second one is 54,17,37