Same denominator

When two fractions have the same denominator, adding them is as easy as it looks: the pieces are already the same size, so you just count them.

Add the tops, keep the bottom

1/4 + 2/4: one piece plus two more of the same size makes three.

Add the numerators (1 + 2 = 3), keep the denominator (4): 3/4. The bottom number never changes — the pieces stay the same size.

Subtracting works the same

5/6 − 2/6 = 3/6, then simplify → 1/2. Same rule: subtract the tops, keep the bottom, and simplify the answer.

The denominator only stays put because the pieces match. That's exactly why the next lesson — different denominators — needs one extra step first.