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Absolute Value
Students should be able to:
- represent numbers less than zero by extending the number line.
What is an integer?
It's a cold winter morning. You turn on the television and the weather man says that the temperature outside is "minus 10 degrees". The number minus ten is actually the number -10, or negative ten, an integer. The term integer is meant to describe the signed numbers.
A formal definition would be integers are all of the whole numbers and their opposites. Remember, whole numbers are the numbers 0, 1, 2, 3, 4, 5,...and so on. These numbers are positive numbers because they are to the right of 0 on the number line. Up until now you have always written these without a sign, but now you will probably be putting the + in front of them. So the number 5 is can be written +5.
Every positive number has an opposite on the other side of the number line. These are the negative numbers. They are the numbers to the left of zero. Every negative number has the - sign. So negative five is written -5. 0 is neither positive nor negative.
Look at the number line below. Push the button to see the opposites of the integers between -5 and +5..
Representing Integers
Every integer stands for a number in the real world. Negative integers are used to represent situations when something has been lost (as in money) or dips below zero (like the temperature example above). Positive integers represent situations when something has been added (such as yardage in a football game) or is above zero (like sea level).
Integers are used in football to represent gains and losses. If a player runs forward, then he gains positive yards. If he is tackled backwards, then he gains negative yards. If a team gains ten yards, then they have a first down.
Look at the football field below. Push the arrows to see if the team will get a first down.
- Constitution Webquest
- Slavery in America
- Waves of Immigration
- Declaration of Independence