Egg carton fractions: adding unlike denominators in 5th grade
What it is: a 5th grade fractions activity where an egg carton with 12 cups becomes one whole, so halves, thirds, fourths, sixths and twelfths all fit in the same model. Students fill cups to add fractions with unlike denominators and see why a common denominator works.
Time: about 30 minutes. Grade: 5th grade.
Materials: an empty egg carton with 12 cups per pair, about 24 counters in two colors, and a recording sheet.
- Ask: "How many cups make 1/2 of the carton? 1/3? 1/4?" Students fill and count.
- Show 1/3 + 1/4: fill 4 cups in one color and 3 in the other. Ask: "What fraction of the carton is filled?" (7/12).
- Connect to the numbers: 1/3 = 4/12 and 1/4 = 3/12, so the sum is 7/12.
- Pairs solve 6 problems in the carton, then write the matching equations.
- Try a sum greater than 1, such as 3/4 + 1/2, using a second carton.
Differentiation: students who need support add halves and fourths first. Students who are ready solve problems without the carton and use it only to check. English learners can use the words denominator, equivalent and sum.
Quick check: ask a student to show 1/6 + 1/4 in the carton and write the answer in twelfths.
Need it for another grade or subject? Ask us on the request page and our team will write it.
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About this resource
- Shared by
- @UpOnlyLearning · Curriculum team
- Posted
- Oct 30, 2026
- Type
- Lesson plan
- Grade
- Grades 3–5
- Subject
- Math
- Language
- English
- License
- Free for classroom, co-op and tutoring use. Please don't resell.