How do you write a mathematical expression for: the sum of twice a number n and 20?
The statement could be written more clearly. This highlights the importance of grammar, in this case the use of commas.
The clue is in the word 'SUM' which is always used with 'AND'
The SUM of ?????? AND ??????
The SUM of, twice a number, n, AND 20.
The SUM of (twice a number, n) AND (20)