Express the following English phrase using an algebraic expression.
The sum of 18 and a number n .
Represent "The sum of 18 and a number n " mathematically.

To express “The sum of 18 and a number n” mathematically, you would write the algebraic expression as . This shows that you are adding the constant 18 to the variable , which represents the unknown number.

Another way to think about it is to visualize it: imagine you have 18 apples and you want to find out how many more you will have if you receive more. You simply add them together which gives you . It’s as simple as pie!