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Mathematics · Grade 1

Two-Digit Addition with Models

Learners add within 100 using base-ten blocks, the hundred chart and number lines: adding tens to a two-digit number (34 + 20), adding ones with and without making a new ten (42 + 5 and 47 + 6), and explaining their steps in tens and ones while solving story problems.

  • 3 lessons
  • About 60 minutes
  • Two-digit addition check: 8 questions
  • Ways to answer: fill in the blanks, choose an answer, match pairs, type a number, place on a number line and put in order
See plans Included with Family, Teacher and School plans. Open in PlayOwl

What learners will discover

  • Add a multiple of 10 to a two-digit number by adding tens to tens, for example 34 + 20 = 54.
  • Add a one-digit number to a two-digit number, recognising when 10 ones make a new ten (47 + 6 = 53).
  • Solve addition story problems within 100 and explain the strategy using tens and ones.

Lessons

  1. Add tens 5 steps2 practiceabout 20 min
  2. Add ones and make a new ten 5 steps3 practiceabout 20 min
  3. Solve and explain 6 steps3 practiceabout 20 min
  4. Two-digit 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.
  • Number TrainAll aboard! Load exactly the right number of animals onto the train.

More 1st grade math

Guide for grown-ups