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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"!
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.
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:
The chart below shows place values of whole numbers and decimal numbers:
|
thousands 1,000 |
hundreds 100 |
tens 10 |
ones 1 |
decimal point |
tenths 1/10 |
hundredths 1/100 |
thousandths 1/1000 |
| . |
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!
Example:
In the number 245.604, name the digit in each place value spot using the place value chart.
|
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.
|
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.
In the Got It? section, you will practice place value with interactive games.
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Resources Referenced in the Lesson
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