TOPIC 9 · GRADE 4 BRIDGE
Common Denominators and Unlike Parts
Rename unlike pieces before combining them, beginning with tenths and hundredths.
MA.4.FR.2.3 · Grade 5 enrichmentBIG IDEA
Fractions can be added only after the pieces use a common unit. Equivalent fractions rename both amounts with the same denominator.
WHAT TO KNOW
- In Grade 4, 3/10 becomes 30/100 so it can combine with hundredths.
- A common denominator is a shared piece size, often found with common multiples.
- For 1/2 + 1/3, sixths work: 3/6 + 2/6 = 5/6.
WATCH OUT
Adding tops and bottoms separately changes the piece size and is not valid.
TRY IT
Overlay fraction grids to find a shared partition before adding.