Adding or Subtracting 10 and 100
Aligned to 2.NBT.B.8 — Common Core State Standards for Mathematics.
What this lesson teaches
When you add 10, only the tens digit changes. When you add 100, only the hundreds digit changes. Do it in your head.
Worked example
Start with 254. Add 100: the hundreds go from 2 to 3, so 254 + 100 = 354.
Practice questions
- What is 463 + 10?
- What is 520 - 100?
- What is 318 + 100?
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 o restar 10 y 100
Cuando sumas 10, solo cambia el dígito de las decenas. Cuando sumas 100, solo cambia el dígito de las centenas. Hazlo de memoria.
Ejemplo: Empieza con 254. Suma 100: las centenas pasan de 2 a 3, entonces 254 + 100 = 354.
More Number & Operations in Base Ten lessons
Adding and Subtracting within 1002.NBT.B.5Hundreds, Tens, and Ones2.NBT.A.1Counting and Skip-Counting2.NBT.A.2Reading and Writing Numbers to 10002.NBT.A.3Comparing Three-Digit Numbers2.NBT.A.4Adding Several Two-Digit Numbers2.NBT.B.6
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