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Mathematics · Grade 2

Add Two- and Three-Digit Numbers

Learners add within 100 and then within 1,000 by adding hundreds to hundreds, tens to tens and ones to ones, making a new ten or a new hundred when a place gets full. They add up to four two-digit numbers by looking for friendly pairs, explain why their strategies work, and check answers by estimating.

  • 3 lessons
  • About 70 minutes
  • Addition check: 8 questions
  • Ways to answer: fill in the blanks, choose an answer, type a number, place on a number line and put in order
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What learners will discover

  • Add two two-digit numbers within 100 using place value (tens with tens, ones with ones, making a new ten when needed).
  • Add three-digit numbers within 1,000, composing a new ten or hundred when needed, and add up to four two-digit numbers.
  • Explain why an addition strategy works using place value, and check an answer by estimating.

Lessons

  1. Add within 100 6 steps3 practiceabout 23 min
  2. Bigger sums 5 steps3 practiceabout 24 min
  3. Explain and check 6 steps3 practiceabout 23 min
  4. Addition check 8 questions at the end

Keep exploring

Games to practice with

  • Number-Line HopHelp the frog hop to the right number — from counting to negative fractions.
  • Paint by AnswersSolve each space, dip your brush and watch a picture come to life.
  • Place-Value WorkshopBuild numbers with rods and cubes — and trade ten ones for a ten.

More 2nd grade math

Guide for grown-ups