Counting by ones to 120

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SWBAT count by ones to extend a counting sequence up to 120.

Big Idea

Count me in! In this lesson students will learn to extend a counting sequence starting at any number.

Activating Strategy

10 minutes

I start this lesson by giving each child a ten frame, counters, and a number card (numbers 0-10).  The children will subtract their number from 10.

First, have children place red counters to fill the ten frame. Then have them model the subtraction by flipping over the counters to show the number being subtracted.  Invite children to share their work and explain how the number of red counters remaining is the difference between the two numbers.

Teaching Strategies

15 minutes

Display a hundreds chart.  Have children look for patterns in the chart. Point to the row showing 51 through 60.  Guide the discussion:

  • What do you notice about each number in a row as you count? (The first digit stays the same until the last column, and the second digit increases by 1 until the last column.)

Read the following problem aloud.

Debbie saw this page in a puzzle book. Two rows of numbers are missing. Use what you know about counting to write the missing numbers.

Hand out a hundreds chart with the first two rows missing (1-20 missing).  See attached resources.  Direct children’s attention to the hundreds chart.

  • What is the first number you see? (21)
  • What is the number right after 21? (22) Is it less than or greater than 21? (It is greater than 21.)
  • So will the missing numbers be less than or greater than 21? (They will be less than because they come before 21.)
  • What number will you write in the first square on the hundred chart? (1)

Count aloud with children from 1 to 21. Then have children fill in the missing numbers in the hundreds chart.  Discuss how each number in a hundred chart is one more than the one before it.

Independent Practice

30 minutes

For the independent practice portion of this lesson, I hand out a counting chart from 1-120.  I like to use this to allow the children the opportunity to look at and understand the pattern of counting.  This provides them with a visual representation to help with conceptualizing the standard.

Have children look at the counting chart. Discuss how it is like a hundreds chart.  Guide the discussion:

  • At what number does a hundred chart start? end? (1; 100)
  • At what number does the counting chart start? end? (1; 120)

Explain that the counting chart shows two more rows than a hundred chart. Tell children that once they count to 100, the counting sequence continues with 100 by using the numbers 1 through 99.

  • How is counting from 101 to 120 similar to counting from 1 to 20? (Possible answer: It is the same except you say one hundred before each number.)

 For struggling students, I use a counting chart and use a piece of paper to cover the fifth through tenth rows, point to number 24 and ask:

  • What number comes after 24?

Continue in the same manner with the rest of the numbers through 30.

Then use a sheet of paper to cover the third through tenth columns.  Point to the number 102, and ask:

  • What number comes after 102?
  • How is counting forward from 102 like counting forward from 2? (The numbers go in the same order, but instead of just saying three, four, five, you need to say one hundred first, so the numbers are one hundred three, one hundred four, one hundred five.)

Have children use the chart to count forward from a variety of numbers.

In this video, the student is telling me about the pattern on the hundreds chart when counting by ones.


5 minutes

To close out the lesson, I like to put random numbers on index cards/post it notes, from a counting chart (1-120) and give one to each student.  I then have the students line themselves up in order in the front of the room.