Algebra & Expressions
Adding Monomials
Monomials can only be added if they are "like terms" — same variable and same exponent. Add the coefficients and keep the variable part.
Watch & Learn
Watch a clear, friendly video explanation of Adding Monomials:
Watch on YouTube →Opens a YouTube search for the best tutorial videos on this topic.
Worked Examples
Follow along with these step-by-step examples. Take your time — there's no rush!
Problem
Add: 5x² + 3x²
Step-by-Step Solution
Both terms have x² — they are like terms.
Add the coefficients: 5 + 3 = 8.
Keep the variable: x².
Answer
8x²
Problem
Simplify: 7xy + 2xy − 3xy
Step-by-Step Solution
All three terms have xy — they are like terms.
Add/subtract coefficients: 7 + 2 − 3 = 6.
Answer
6xy
Problem
Simplify: 4x³ + 2x² + 5x³
Step-by-Step Solution
Identify like terms: 4x³ and 5x³ are like terms. 2x² is different.
Add like terms: 4x³ + 5x³ = 9x³.
2x² stays as is.
Answer
9x³ + 2x²
Problem
Simplify: 10a²b − 3a²b + a²b
Step-by-Step Solution
All three terms have a²b — they are like terms.
Combine coefficients: 10 − 3 + 1 = 8.
Answer
8a²b
Problem
Simplify: 6x + 4y − 2x + 3y
Step-by-Step Solution
Group like terms: (6x − 2x) + (4y + 3y)
6x − 2x = 4x
4y + 3y = 7y
Answer
4x + 7y
Your Turn — Practice Problems
Try all 5 problems on your own first. Write out your work — that's how it sticks!
💡 Tip: Don't peek at the answers until you've genuinely tried each one.
Add: 6x + 4x
Add: 3y² + 8y²
Simplify: 9ab − 4ab + ab
Simplify: 5x² + 3x + 2x²
Can you add 4x² and 4x? Why or why not?
Simplify: 12m³ − 5m³
Simplify: 3a + 2b + 5a − b
Simplify: 7xy + 3xy − 2xy
Simplify: 4x² + 0x²
Simplify: 6p − 6p
Simplify: 2x³ + 5x² + 3x³ − x²
Simplify: 10ab − 3ab + 2ab
Finished all 12? Give yourself a pat on the back — then check your work!
Keep going — you're on a roll!
Every topic you master is another step on your journey.
Explore More Topics