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