Find the missing number.

2 3 31
5 7 368
1 4 ?

The missing number is 40.

Explanation:
(2 + 5) = 7
(3 + 7) = 10
(7 x 10) = 70

(31 + 368) = 399
(399 % 10) = 9
(399 / 10) = 39

Therefore, the missing number is:
(1 + 4) = 5
(5 + 39) = 44