Lesson 10 Tens and Tens, Ones and Ones

    • Let’s add two-digit numbers.

Warm-up How Many Do You See: Tens and Ones

How many do you see?
How do you see them?

  1. Four ten frames. 1 full, red counters. 1 with 3 red counters. 1 full, yellow counters. 1 with 6 yellow counters.
  2. Four ten frames. 1 full red counters. 1 with 8 red counters. 1 full, yellow counters. 1 with 2 yellow counters.
  3. Four ten frames. 1 full, red counters. 1 with 4 red counters. 1 full, yellow counters. 1 with 8 yellow counters.

Activity 1 Priya‘s Work

Find the value of .

Priya’s work

Drawing to show 63. Group of 5 tens, labeled 50. Group of 10 ones and 3 more ones, labeled 13. Number 63.

How did Priya find the value?

Activity 2 Finish the Work

Problem 1

Each expression shows a first step to find the number that makes each equation true.
Finish the work to find the number that makes each equation true.
Show your thinking using drawings, numbers, or words.

  1. First step:

    Base ten drawing. Group of 2 tens and 5 tens, circled. 8 ones and 6 ones. 

  2. First step:

    Base ten drawing, 2 groups. Top, 2 tens, 7 ones. Bottom, 4 tens, 4 ones.

Problem 2

Find the value of each sum.
Show your thinking using drawings, numbers, or words.

Activity 3 Introduce Number Puzzles: Within 100 with Composing

These number puzzles have addition equations with two-digit numbers. Use the digit cards to make each equation true. Remember that you can only use each card once on a page.

Practice Problem

Problem 1

  1. Find the value of .
    Show your thinking using drawings, numbers, or words.

  2. Can you find the value in a different way?