What's the missing number?

Front

What is the missing number? 48, 47, 45, 46

Back

45

Front

What is the missing number? 38, 37, 36, 35

Back

38

Front

What is the missing number? 20, 21, 22, 23

Back

22

Front

What is the missing number? 31, 30, 29, 28

Back

29

Front

What is the missing number? 42, 43, 44, 45

Back

42

Front

What is the missing number? 10, 11, 12, 13

Back

12

Front

What is the missing number? 5, 6, 7, 8

Back

7

Front

What is the missing number? 15, 16, 17, 18

Back

17

Front

What is the missing number? 25, 26, 27, 28

Back

27

Front

What is the missing number? 35, 36, 37, 38

Back

37