Lesson 20 Greater Than or Less Than than 20?

    • Let’s decide if there are greater or less than 20 things in a group.

Warm-up Estimation Exploration: Close to 10

a group of dots

Record an estimate that is:

too low

about right

too high

Activity 1 Use 10 to Estimate

Write “greater” or “less” to finish each sentence.

  1. I think there are than 10 pencils.

    three colored pencils, yellow, red, blue

    How many pencils are there?

  2. I think there are than 10 pencils.

    pictures of pencils

    How many pencils are there?

  3. I think there are than 10 pencils.

    four pencils

    How many pencils are there?

  4. I think there are than 10 pencils.

    photo of colored pencils

    How many pencils are there?

  5. I think there are than 10 pencils.

    photo of colored pencils

    How many pencils are there?

Activity 2 Could She Be Right?

  1. Elena says there are about 11 snowflakes.
    Do you think she could be right?
    Why or why not?

    group of snowflakes

  2. Elena says there are about 8 flowers.
    Do you think she could be right?
    Why or why not?

    group of flowers

  3. Elena says there are about 11 suns.
    Do you think she could be right?
    Why or why not?

    a group of suns

Activity 3 Centers: Choice Time

Choose a center.

Shake and Spill

Center. Shake and Spill.

Number Race

Center. Number Race.

Grab and Count

Center. Grab and Count.

What’s Behind My Back?

Center. What's Behind My Back.

Pattern Blocks

Center. Pattern Blocks.