CCSS.MATH.4.NF.B.3✓ Florida Department of Education (FLDOE) AlignedAcademic Year 2026–27
Adding & Subtracting Fractions with Like Denominators
Decompose fractions into sums of unit fractions and add/subtract mixed numbers with common denominators.
Why It Matters:Essential for combining measured recipe ingredients, calculating lumber lengths, and tracking portions.
Curated Video Instruction
● Verified Active EmbedSTEP-BY-STEP PROOF
Worked Example
Compute 2 (3/8) + 1 (7/8) and express as a simplified mixed number:
1
Add whole numbers and fraction parts separately
(2 + 1) + (3/8 + 7/8) = 3 + 10/8
Combine whole integers and fractional eighths.
2
Convert improper fraction 10/8 to mixed number
10/8 = 1 (2/8) = 1 (1/4)
8 eighths make one whole.
3
Combine whole numbers
3 + 1 (1/4) = 4 (1/4)
Yields the final simplified mixed number.
✓Verification Check
Convert to improper fractions: 19/8 + 15/8 = 34/8 = 4 (2/8) = 4 (1/4).
34 / 8 = 4.25
•
4 (1/4) = 4.25 (Verified)
⚠️ Common Pitfalls & Misconceptions
Adding denominators together
✗ Thinking 2/5 + 1/5 = 3/10✓ Denominators state the size of the part; only numerators add: 2/5 + 1/5 = 3/5
Adding denominators cuts the parts in half rather than accumulating more parts.
INTERACTIVE DRILLS
Guided Practice
Practice Question1 of 1
Step-by-step Feedback
What is 5/9 + 2/9?
MASTERY BENCHMARK
Official Assessment Quiz
Formal Assessment
Adding & Subtracting Fractions with Like Denominators
Passing Criteria:70% or higher
Question 1 of 1
What is 3 (1/4) - 1 (3/4)?
Education to Career Navigation
Where This Lesson Leads
Bakers and Construction Craftsmen add fractional measurements continuously.