How do you define a variable and write an algebraic expression for the phrase: 12 less than a number?

1 Answer
Oct 14, 2015

The expression is x-12.

Explanation:

12 less than a number means to subtract 12 from that number.

So, 12 less than 20 is 8, because is 20-12, 12 less than 12 is 0, because it's 12-12, and so on.

But since you don't know which number you need to subtract from, it's a variable, and you can call it as you like, usually x.

So, using the variable we can write an expression that holds for any number, and which always means "take 12 away from my number". If your number is x, the expression would be x-12