It could be 62.
12
31
38
20
It is 38, the middle number when they are arranged in order.
The next number is 20.
31
31.
12
The HCF of 38 and 40 is 2
38
31
38
In a series of numbers, there are rhythms that change. In the order of 100, 140, and 40, the number that would come next would be 80 because 40 should be added.
20
6
8, each number is a fifth of the last.