Add and Subtract Big Numbers
Aligned to 3.NBT.A.2 — Common Core State Standards for Mathematics.
What this lesson teaches
Line up numbers by place value: ones under ones, tens under tens, hundreds under hundreds. Add or subtract each column, and regroup when needed.
Worked example
Add 256 + 137. Ones: 6 + 7 = 13, write 3 and carry 1. Tens: 5 + 3 + 1 = 9. Hundreds: 2 + 1 = 3. The answer is 393.
Practice questions
- Solve 342 + 215.
- Solve 500 − 168.
- A store had 620 books and sold 145. How many are left?
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 Números Grandes
Alinea los números por su valor posicional: unidades con unidades, decenas con decenas, centenas con centenas. Suma o resta cada columna y reagrupa cuando haga falta.
Ejemplo: Suma 256 + 137. Unidades: 6 + 7 = 13, escribe 3 y lleva 1. Decenas: 5 + 3 + 1 = 9. Centenas: 2 + 1 = 3. La respuesta es 393.
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