Question

How do you write "Twice the the quantity a number and 3."?

Answer 1

`2(n+3)`

Explanation:

a number and 3:

if the number is denoted `n`, then 'a number and 3'#
-> `'a number +3'`
-> `'n+3'`

to have twice this whole quantity (instead of, for instance, only n being doubled:

put `'n+3'` in brackets
->`(n+3)`

then to double it, put a 2 before the whole expression (n+3)
-> `2(n+3)`

the final expression: `2(n+3)`

Answer 2

2(n + 3) is probably what you are looking for.

Explanation:

Twice the quantity usually means, "get ready for parentheses".
Inside the parentheses, expect a sum when the statement just says "and". So I would write 2(n + 3).