Section C: Practice Problems Count Groups of 11–20 Images

Section Summary


In this section, we counted groups of up to 20 things.

We counted things in lines, arrays, circles, and on 10-frames.

Array of 12 squares.
Ten frame with counters.
Line of rectangles.

We wrote numbers to show how many images there are.

Problem 1 (Lesson 11)

  1. How many triangles are there?

    Triangles. 2 rows of 7.

    There are triangles.

  2. Lin wrote the equation to show the number of hexagons.

    Color the hexagons to show Lin’s equation.

    Hexagons. 3 rows, 4 in each row.

Problem 2 (Lesson 12)

  1. How many squares are there?


    There are squares.

  2. How many circles are there?

    Two rows of circles. First row, 10. Second row, 10.

    There are circles.

Problem 3 (Exploration)

Pick some of the flowers in the picture.

Drawing of plants and flowers.
  1. How many are there?

  2. Share your answer with a partner.
    Can you guess which flowers your partner counted?

Problem 4 (Exploration)

Pick a shape in one of the designs and figure out how many there are.

Exploration design.