Lesson 2 Explore Expressions and Sums

    • Let’s write addition expressions and find the sum of two numbers.

Warm-up Choral Count: Count to 41

  • Count by 1, starting at 0.

  • What patterns do you see?

Activity 1 Matching Dot Cards and Expressions

Problem 1

Match each pair of dots to an expression. Then, find the total.

2 dot cubes. First cube, 4. Second cube, 2.  
2 dot cubes. First cube, 5. Second cube, 3.
2 dot cubes. First cube, 6. Second cube, 4.
2 dot cubes. First cube, 3. Second cube, 2.  
2 dot cubes. First cube, 4. Second cube, 3.  

expression

total

Problem 2

Draw the missing dots to match the expression. Then, find the total.

  1. Expression:

    2 dot cubes, both blank.

    Total:

  2. ​​​​​​Expression:

    2 dot cubes, both blank.

    Total:

  3. Expression:

    2 dot cubes, both blank.

    Total:

Problem 3

Write the missing expression to match the dots. Then, find the total.

  1. 2 dot cubes. First cube, 1. Second cube, 2.  

    Expression:

    Total:

  2. 2 dot cubes. First cube, 3. Second cube, 1.

    Expression:

    Total:

Activity 2 Introduce Check it Off: Add within 10

Take turns choosing two cards, finding the sum, and writing an addition expression. You may have more than one expression for each sum.

Practice Problems

Problem 1

Circle the expression that matches the dots.

2 groups of dots. First group, 4. Second group, 3.

Problem 2

Circle the dots that match the expression:

  1. 2 groups of dots. First group, 5. Second group, 1.
  2. 2 groups of dots. First group, 4. Second group, 1.
  3. 2 groups of dots. First group, 4. Second group, 2