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### Course: Arithmetic>Unit 18

Lesson 2: Negative symbol as opposite

# Negative symbol as opposite

Opposites in math involve flipping the sign of a number. A positive number's opposite is the same number but negative, and vice versa. The negative symbol represents the concept of "opposite." When multiple negative symbols are applied, each one flips the number across the number line, resulting in a positive or negative value.

## Want to join the conversation?

• how about in multiplication when -4 x 4 = ?

• I know this is 4 years after, but still.
Think about a number line. When you multiply negative numbers you go more to the left of the number line, where there are more negative numbers. Just like 4x4=16, -4x4=-16. If you multiply +4 by 4, then you're moving to the right of the number line. The same idea applies.
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• they is a vid that revils it on earth or space courses
(1 vote)
• bruh he says opposite so many times in the video
• lol he does say opposite so much tho
• At , Sal says that he will use this symbol # to represent "number". Where does this symbol come from and why does it represent "number"?
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• me(i do ixl)
• Math if my worst enemy sadly
• so is spelling
• I dont get numbers like-(-7)
• One way to think of a negative sign is just 'inverting' or flipping whatever comes after it. If there is no negative sign, the positive sign (+) is implicit (assumed).
This means that 1 negative sign flips the sign from + to -.
A second negative sign (like -(-7)) flips the first negative sign back to a +.
A third (like -(-(-7))) would flip the sign to - again.

So, an odd number of - signs (1, 3 etc.) gives you a negative number, while an even number of - signs (0, 2 etc) gives you a positive number.
• at he explains that -|-3| when done is positive 3 but shouldn't it be -3
• You are using the absolute value bars which you give the correct answer, but Sal is not talking about absolute value, he uses parentheses such as -(-3) which is two negatives in a row and the answer is positive.