The Value of a Number: Place Value

Contributor: Erika Wargo. Lesson ID: 12388

When is a number 3 not a number 3? When it moves left or right. In other words, it depends on where it is sitting on a place value chart. Learn the importance of the tiny decimal point and the "ths"!

categories

Elementary

subject
Math
learning style
Visual
personality style
Beaver
Grade Level
Intermediate (3-5)
Lesson Type
Skill Sharpener

Lesson Plan - Get It!

Audio:

You are at the big footrace. At the end, the board flashes that the fastest runner finished with a time of 2.405 minutes to win the race. How do you read the number 2.405?

The position, or place, of a digit in a number is important for determining the value of the number.

Each place value position has a specific value. Take a moment to review place value of whole numbers and decimals with a video. As you watch Math Antics-Decimal Place Value, take notes on information that is new to you. Also, focus on finding the answers to the following questions:

  • What pattern occurs as numbers increase to the left of the decimal point?
  • What pattern occurs as numbers increase to the right of the decimal point?
  • What are the three place-value spots to the right of the decimal point?

 

Discuss the questions and what you learned with a parent or teacher.

The chart below shows place values of whole numbers and decimal numbers. The decimal point is used as a guide to help you find the value of each place. As you move left on the place value chart, the value is 10 times larger than the place to the right. As you move to the right on the place value chart, the value is 10 times smaller than the place to the left. Don’t forget that the place value positions to the right of the decimal are written with a “ths” at the end of the word!

thousands

1,000

hundreds

100

tens

10

ones

1

decimal

point

tenths

1/10

hundredths

1/100

thousandths

1/1000

        .      

 

Example:

In the number 245.604, name the digit in each place value spot using the place value chart.

  1. tenths - 6
  2. thousandths - 4
  3. hundredths - 0

thousands

1,000

hundreds

100

tens

10

ones

1

decimal

point

tenths

1/10

hundredths

1/100

thousandths

1/1000

  2 4 5 . 6 0 4

 

Take a look at the problem from the beginning of the lesson:

The fastest runner finished with a time of 2.405 minutes to win the race. How do you read the number 2.405?

thousands

1,000

hundreds

100

tens

10

ones

1

decimal

point

tenths

1/10

hundredths

1/100

thousandths

1/1000

      2 . 4 0 5

 

When reading a decimal number, say the word “and” where you see a decimal point. The number after the decimal point is read as it appears with the place value spot of the last digit.

2.405 is read as two and four hundred five thousandths.

Discuss with a parent or teacher:

  • When reading or writing a decimal number, what word is used to identify a decimal point?
  • How does place value relate to writing money amounts?
  • Think about the amounts $4.50 or $3.25; why does money only have two decimal place value spots?

In the Got It? section, you will practice place value with interactive games.

Elephango's Philosophy

We help prepare learners for a future that cannot yet be defined. They must be ready for change, willing to learn and able to think critically. Elephango is designed to create lifelong learners who are ready for that rapidly changing future.