Answer: (n - 2) + 20
Explanation:
We will create a mathematical expression using the statement given. 'Less' implies subtraction, let n be a number.
'than a number' ➜ n
'Two less' ➜ - 2
'plus twenty.' ➜ + 20
'Two less than a number plus twenty.' ➜ (n - 2) + 20