If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

### Course: Class 8 (Foundation)>Unit 1

Lesson 1: Adding and subtracting integers

# Intro to negative numbers

Mysterious negative numbers! What ARE they? They are numbers less than zero. If you understand the nature of below zero temperatures, you can understand negative numbers. We'll help. Created by Sal Khan.

## Want to join the conversation?

• Is -1 more or less than 0.1
• -1 is a negative number, which makes it less than any other positive number. 0.1 is positive, so 0.1 is greater than -1. You can compare then to zero like this: `-1 < 0 < 0.1`.
• how do you know that you have to put negative?
• Anything that is below zero is negative, with a sign like this "-6"
U put a negative sign when any number is below zero.
• Let me get this straight those that mean the bigger the number with the - sign it means its bigger for example -101<-1 is this right or wrong?
• -1 is definitely correct because the negative sign essentally makes the bigger one less for example -100 and -1 the ngitive 1 is bigger because its closer to zero
• OK can we divide a neg and a neg?
• Yes, it becomes positive.
-8/-2 =4
8/2=4
-8/2=-4
8/-2=-4
• Why does doing an operation with negative numbers always differ from operating on only positive numbers, apart from that one type uses negative numbers?
• Here are some simple rules to handle Addition and Subtraction of Integer Number. Hope this can help you:

Notes: The sign of an integer is written right in front of that number
When a number is written without a sign in front, then it is a positive number

I- ADDITION: Very easy if you remember these 3 rules

Rule No.1: The sum of 2 positive integers is always positive
Example: (+5) + (2) = +7

Rule No.2: The sum of 2 negative integers is always negative
Example: (-5) + (-2) = -7

Rule No.3: When adding a positive integer to a negative integer, subtract the
larger absolute value to the smaller absolute value; and then use
the sign of the larger for the final answer.
Example: (+5) + (-2) = +3
(-5) + (+2) = -3

Special Case of Rule No. 3: When adding a positive integer to a negative integer of the same absolute value, the result is 0

II- SUBTRACTION:

When subtracting an integer, add to the opposite number of that integer, and
Example: (+500) – (-100) becomes (+500) + (+100) = +500 + 100 = 600 (Rule 1)
(-16) – (-9) = -16 + 9 = -7 (Rule No. 3 of Addition)
• How can we describe negative numbers?
(1 vote)
• You could also think of a negative number as anything to the left of zero on the number-line , and positive is anything to the right.
• So for negative numbers if it is more to the left it is greater right?
• No, he explains in his video at that -100 is SMALLER than -1 which would make numbers to the left smaller than the numbers to the right. This also explains why you would say that -5 is less than 5 with -5 being more to the left. I am basically just reinstating what 26anguyen19 has said.