Adding and Subtracting Like Fractions
Aligned to 4.NF.B.3 — Common Core State Standards for Mathematics.
What this lesson teaches
A fraction like 5/8 is just five copies of the unit fraction 1/8 added together. When denominators are the same, add or subtract the numerators and keep the denominator the same.
Worked example
2/8 + 3/8. Both are eighths, so add the numerators: 2 + 3 = 5, keep the denominator 8. Answer: 5/8. You can see it as 1/8 + 1/8 + 1/8 + 1/8 + 1/8 = 5/8.
Practice questions
- Add: 3/6 + 2/6.
- Subtract: 7/10 - 4/10.
- Write 4/5 as a sum of unit fractions, then find 4/5 - 1/5.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Sumar y restar fracciones iguales
Una fraccion como 5/8 es solo cinco copias de la fraccion unitaria 1/8 sumadas. Cuando los denominadores son iguales, suma o resta los numeradores y deja el denominador igual.
Ejemplo: 2/8 + 3/8. Ambas son octavos, asi que suma los numeradores: 2 + 3 = 5 y deja el denominador 8. Respuesta: 5/8. Lo puedes ver como 1/8 + 1/8 + 1/8 + 1/8 + 1/8 = 5/8.
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