Unit 2 Math Integers

Unit 2 Study Guide

Integer Introduction Video

Determine the Opposite Video

Comparing Integers QUIZIZZ    Game Code: 647498


the set of whole numbers and their opposites
Negative Numbers
numbers that are less than zero
Positive Numbers
numbers that are greater than zero


In mathematics so far, you have learned about some different kinds of numbers. You learned about whole numbers, fractionsdecimals and percentages. In this Concept, you are going to learn about integers.

What is an integer?

An integer is a member of the set of whole numbers and their opposites.

To better understand integers, let’s first think about some real life situations where you might have seen integers used before.

Integers can be thought of as positive and negative numbers.

Let's think about temperature.

If you look at this thermometer, you will see that the temperature is This is 79 degrees above zero.

When we think about temperature, we use integers all the time. You might have heard someone talk about temperatures above or below zero. A temperature that is above zero is positive. A temperature that is below zero is negative.

Integers are positive and negative whole numbers. Said another way, they are whole numbers and their opposites.

How can we write integers?

When writing an integer, we can use a + sign or a - sign. A + sign can be used for a number above zero or a positive number. A positive number can also be written without the + sign. Anegative number should be written using the - sign.

5 degrees below zero

The words “below zero” let you know that this integer is a negative number. Since it is five degrees below zero, we can write the integer negative five.

The answer is -5.

83 degrees

This temperature does not have a "-" sign in front of it, and does not say "below zero" either, it is a positive number. We write the integer positive eighty-three.

The answer is 83 or +83.

There are other real-life situations that use positive and negative numbers too.

One example is with money. A loss of money would be a negative integer. A gain of money is a positive integer.

Jeff earned two hundred dollars working at the farm stand.

Jeff’s money is a gain. He “earned” it. That means that he had an increase in money and not a decrease. An increase or a gain is a positive integer. We can write the two hundred dollars as a positive integer.

The answer is $200.00 or +$200.00.

Sasha spent $45.00 at the clothing store.

Since Sasha spent this money, it is a loss. Therefore, we can say that Sasha’s $45.00 is a negative integer. A negative integer can show a loss of money.

The answer is -$45.00.

The stock market is another real-life situation that uses positive and negative integers all the time.

In this picture the red arrow represents a gain and would be written as a positive integer. The purple arrow represents a loss and would be written as a negative integer.

What are some other key words that mean positive or negative integers?

We have already talked about losses and gains and above zero and below zero.

Profit and loss are two other words that mean positive or negative integers. Profit means positive and loss means negative.

An earning is a positive number.

Spending is a negative number.

Practice writing integers by using key words. Write an integer for each example.

Example A

50 feet below sea level

Solution: -50

Example B

$100.00 was spent

Solution: -100

Example C

A heat wave of 

Solution: +98

Practice Problems - Understanding Integers     (ANSWERS)

Understanding Positive and Negative Numbers - Independent Practice Worksheet    (ANSWERS)

Representing Integers Practice with ANSWERS

Understand A Rational Number As A Point    (ANSWERS)

Understand A Rational Number as A Point Independent Practice  (ANSWERS)

Understand A Rational Number as A Point Matching   (ANSWERS)


Directions: Write an integer to represent each situation.

1. A loss of 20 points

2. A gain of 14 points

3. A profit of $20.00

4. A loss of $18.00

5. An elevation of 500 ft.

6. 200 feet below sea level

7. 8 degrees below zero

8. 78 degrees

9. A decrease of $68.00

10. An increase of $55.00

11. The dow did not rise or fall today.

12. The plane descended at a rate of 15%.

13. The submarine surfaced.

14. The cost and the earnings evened out.

15. The stock market had an overall rate of 18% above.

Practice Answers