Adding Fractions with Like Denominators

Adding Fractions with Like Denominators

Grade: 3rd · Time: ~45 min

Warm-up (5 min)

Draw a pizza cut into 4 equal slices. Color 1 slice. Ask: "What fraction did we color?" (1/4)

Teach (15 min)

When two fractions have the same bottom number (denominator), we add the top numbers (numerators) and keep the bottom the same:

1/4 + 2/4 = 3/4

The bottom stays 4 because the slices are still fourths.

Guided practice (10 min)

• 1/5 + 2/5 = ?
• 3/8 + 4/8 = ?
• 2/6 + 2/6 = ?

Independent practice (10 min)

Have your student invent three of their own like-denominator problems and solve them.

Check for understanding (5 min)

Ask: "Why does the bottom number stay the same when we add?"

Standards

3.NF.A.1 — Understand a fraction as a number on the number line.