Question

5 less than the product of 8 and a number

Answer 1

A - number 
the product of 8 and a:  8a
5 less than the product of 8 and a: $\fbox{8a - 5}$

Answer 2

N-the number

the product of 8 and the number: 8 × n = 8n

5 less than the 8n: 8n - 5