Explanation

If A = 1, FAT = 27, then FAITH = 44.

Sure, each letter represents its position in the alphabet and the values of the letters are summed:

F (6th letter) = 6

A (1st letter) = 1

T (20th letter) = 20

For FAITH:

F (6th letter) = 6

A (1st letter) = 1

I (9th letter) = 9

T (20th letter) = 20

H (8th letter) = 8

So, the value of FAITH is 44.