# Multiplying monomials review

CCSS Math: HSA.APR.A.1
A monomial is a polynomial with just one term. For example, 2a^5 is a monomial. This article reviews how to multiply monomials (e.g., 2a^5 * 3a^2 = 6a^7).
A monomial is a polynomial with just one term, like $2x$ or $7y$. Multiplying monomials is a foundational skill for being able to multiply binomials and polynomials more generally, so it's good to review a few examples.

### Example 1

Simplify.
${(-4x^2)(7x^3)}$
When a number is next to a variable, it means they are multiplied. So,
$(\blueD{-4}\maroonD{x^2})(\blueD{7}\maroonD{x^3})$
is the same as
$(\blueD{-4})(\maroonD{x^2})(\blueD{7})(\maroonD{x^3})$.
Now we can rearrange the factors because multiplication is commutative (a fancy way of saying that the order in which we multiply things doesn't matter).
$\blueD{(-4)(7)}\maroonD{(x^2)(x^3)}$
Then simplify, and we're done!
$\blueD{-28}\maroonD{x^5}$

### Example 2

Simplify.
${(-8a^2)(-5a^6)}$
When a number is next to a variable, it means they are multiplied. So,
$(\blueD{-8}\maroonD{a^2})(\blueD{-5}\maroonD{a^6})$
is the same as
$(\blueD{-8})(\maroonD{a^2})(\blueD{-5})(\maroonD{a^6})$.
Now we can rearrange the factors because multiplication is commutative (a fancy way of saying that the order in which we multiply things doesn't matter).
$\blueD{(-8)(-5)}\maroonD{(a^2)(a^6)}$
Then simplify, and we're done!
$\blueD{40}\maroonD{a^8}$
Want to see another example? Check out this video.

## Practice

Want more practice? Check out this exercise. Also check out this challenge exercise.