Math Background

Lesson: Order Whole Numbers to 100
Developing the Concept

Once the children are comfortable putting numbers in order, introduce ordering numbers on the number line.

Materials: large or small cards numbered 0 – 20 and floor or wall number line

Preparation: Prepare a number line on the floor or wall. Place the numbers 0 and 20 on the number line. Put the other number cards face up in random order in the chalk tray or on a table.

Prerequisite Skills and Concepts: Understand order and count from 0 – 10.

You may choose to do this activity by having the children stand in place on the floor number line holding the large numbers, or you can place the smaller numbers on the wall number line.

  • Say: Today we are going to use a number line to help us put the cards in order.

    Introduce children to the number line. Point out the numbers that you placed on it and the short vertical lines between the numbers.

  • Ask: How can we order numbers on this line?
    Elicit from children that they can use the short lines on the number line to count the missing numbers between the numbers already on the line.
  • Say: I would like you to start at 0 and count to 20 as I point to the short lines on the number line.(Count.)
  • Say: Now we are going to talk about numbers that come just before, just after, and between.

    Place a number such as 6 on the number line.

  • Ask: Who can come up and pick out the number that comes just before 6 and place it on the number line just before 6?
    The child should pick 5.
  • Ask: How do you know that is the correct number?
    Elicit from the child that when they order or count numbers 0 – 10, the 5 comes just before the 6.

    Remove the numbers and place two numbers such as 5 and 7 on the number line with a space between.

  • Say: Look at the two numbers that are on the number line.
  • Ask: Who can find the number that comes between these two numbers?
    The child should choose 6.
  • Ask: How did you know to pick 6?
    The child should say that when he/she counts or orders numbers, 6 comes between 5 and 7.

    Remove the numbers and place a number such as 14 on the number line.

  • Ask: Who can come up and pick out the number that comes just after 14 and place it on the number line just after 14?
    The child should pick 15.
  • Ask: How did you know to pick 15?
    The child should say that when he or she counts or orders numbers, 15 comes after 14.
  • Continue this activity until children are skilled at using the number line. You can also adapt this lesson for larger numbers when you are ready to introduce them to the children.

Wrap-Up and Assessment Hints
Ordering numbers is an essential skill for all mathematical computation. Provide adequate practice and challenge to ensure that children master the skill. Emphasize to children how important it is that they become proficient in ordering the set of numbers from 0 to 100 before they move on to greater numbers.


Houghton Mifflin Math Grade 1