 Place value- numbers to 20 on the number line

# Place value- numbers to 20 on the number line

Place value- numbers to 20 on the number line

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## General

Students start to learn about place value and learn to place numbers on the number line. They learn the tens and ones that make up numbers to 20 and can jump to these numbers on the number line.

K.NBT.A.1

## Relevance

Discuss with students that they use this knowledge of numbers to 20 do work with numbers later.

## Introduction

The interactive whiteboard shows a row of t-shirts with numbers. Ask what the missing numbers are and write them down. Erase the boxes to show the answers. Next take a handful of colored pencils (max of 20) and set them in groups of 10 on the table. Ask a student to come to the front and ask them how many colored pencils there are. Do the same with a number of books.

## Development

On the interactive whiteboard show the tens and ones. Explain that a tens is a group of 10 and ones are the numbers from 1-9. Show MAB blocks on the interactive whiteboard and/or show it in your classroom. Using the blocks, demonstrate what tens and ones are. Next show a chart of tens and ones. Discuss a number that only has ones, 4. In addition to the TO-chart there is a number line with four jumps of 1 to show the number 4. Practice ones as a class. Have students say which tens and which ones are needed to make 8, and show the jumps on the number line. Show the intermediate jumps on the interactive whiteboard. Show that you can also make jumps of 5. That makes getting to your number faster. Next show a chart of tens and ones with a number that contains both. Explain how you jump from 0 to 13 and use the number line next to the chart. Practice tens and ones as a class. The students indicate how many tens and ones are needed in the number 17 and discuss how best to jump to 17 on the number line. Be sure to mark the intermediate jumps. Next a few exercises are given for students to determine how to best jump to a given number on the number line.

Check that students know how numbers to 20 are put together by asking the following questions:
- What is a tens? How do you know?
- What is a ones? How do you know?
- Which jumps can you make on a number line to get to a number?

## Guided Practice

Students first practice indicting which number has been jumped to on a number line. Then they must come up with the jumps needed to get to a given number. First with numbers to 10, and then to 20.

## Closing

Discuss with students that it is important to know how tens and ones work in numbers to 20, so you can learn to work with numbers. Check that students know what ones and tens are and that they can jump to a number on the number line. To practice this, the teacher takes a number of steps or jumps and the students must make a number line to represent the number you show. Show an example first and clearly indicate if your movement is a 1, 5, or 10. A small step is a jump of 1, a big step is a jump of 5, and a jump forward is a jump of 10.

## Teaching Tip

Students who have difficulty with numbers on the number line can be helped by the verbal reminder that the "ten" is in tens, and "one" is in ones. That tells them where they need to look and which numbers they are dealing with. They can also be supported by the use of manipulatives to show the clear difference between tens and ones. 