The Missing Pizza Mystery: Adding Fractions with Unlike Denominators Visually
Shared by A STEM Educator
Students will be able to add fractions with unlike denominators by creating equivalent fractions using visual models and identifying a common denominator (CCSS.MATH.CONTENT.5.NF.A.1).
Lesson Overview
Students use visual fraction models to build understanding of equivalent fractions before adding fractions with unlike denominators, progressing from same-denominator review through multi-step unlike-denominator addition in a pizza mystery context.
Materials
- Vertical whiteboards or chart paper
- Dry-erase markers (multiple colors)
- Random grouping tool
- Printed fraction strips (optional support)
- Four-quadrant note-taking template
- Exit slip half-sheets
Scaffolded Task Progression
The pizza was cut into 8 equal slices. Suspect A ate 2/8 of the pizza. Suspect B ate 3/8 of the pizza.
Draw a fraction bar divided into 8 equal parts. Shade Suspect A's slices in red and Suspect B's slices in blue.
How much pizza did they eat together? Write the addition equation.
[ Interactive graph / diagram — available in the full lesson ]
A different pizza was cut into 6 equal slices. Suspect A ate 1/6. Suspect B ate 4/6.
Draw a fraction bar divided into 6 equal parts. Shade each suspect's portion in a different color.
Write the addition equation. Did they eat more or less than a whole pizza? How do you know from your model?
[ Interactive graph / diagram — available in the full lesson ]
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