Find the unknown value below!

SOLUTION!

Represent the 1st term as a product of 2 digits such that the sum of the 2 digits is equal to the middle term.

8 can be written as 2*4

Sum of 2 and 4 is 6 which is the middle term.

In the same way 55=11*5

Middle term(unknown) =11+5=16.

Solution: