Collecting Like Terms

1 · One letter 2 · Two letters 3 · Letters and numbers 4 · Two letters and numbers 5 · Adding expressions 6 · Subtracting expressions 7 · Terms in $x^2$ and $x$ 8 · Mixed powers and products 9 · Products: $ab$ and $ba$ 10 · Adding or multiplying: $2n$ or $n^2$ Mixed 1–10