Add and Subtract Fractions (Like Denominators)

Two fractions have like denominators when their bottom numbers are exactly the same. Like denominators mean every piece is the same size, so you can add or subtract by simply counting pieces — no resizing needed. The denominator never changes; only the numerators move.

Adding Fractions with Like Denominators

• Check that both fractions share the same denominator (same-size pieces).
• Add the numerators together. The sum becomes the new top number.
• Keep the denominator the same — do not add the bottoms.
• Example: 2/8 + 3/8 = (2 + 3)/8 = 5/8.

Subtracting Fractions with Like Denominators

• Check that both fractions share the same denominator.
• Subtract the second numerator from the first. The difference becomes the new top number.
• Keep the denominator the same — never subtract bottoms either.
• Example: 5/6 - 2/6 = (5 - 2)/6 = 3/6, which simplifies to 1/2.

Simplifying the Result

• After adding or subtracting, check whether the answer can be reduced.
• Find the greatest common factor (GCF) of the numerator and denominator.
• 3/6: GCF of 3 and 6 is 3, so 3/6 simplifies to 1/2.
• A fraction is in simplest form when the GCF of its top and bottom is 1.

Why the Denominator Stays the Same

• The denominator names the size of each piece — eighths, sixths, fifths, etc.
• When the pieces are the same size, putting more pieces together does not change their size.
• Adding pieces just changes how many you have, not how big each one is.
• That is why only the numerator (the count) changes during the operation.