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Applications of Negative Numbers & Absolute Value. In Algebra County. Negative Numbers are found in weather reports, but not in sunny Florida!. Zero. Down here, temperatures are negative. Negative Numbers are found in stock market quotes. There, the stock market went down.
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Applications of Negative Numbers&Absolute Value In Algebra County
Negative Numbers are found in weather reports, but not in sunny Florida! Zero Down here, temperatures are negative.
Negative Numbers are found in stock market quotes There, the stock market went down.
Negative Numbers are found in banking. Checks are “subtracted” from the bank statement.
ADDING INTEGERS IN ALGEBRA COUNTY
If it’s 70 degrees outside, and the temperature gets 10 degrees cooler, how can we write it? If it’s 5 degrees outside, and the temperature gets 10 degrees colder, how can we write it? A positive added to a negative takes the sign of the largest “number.” We subtract. If it’s -10 degrees outside, and the temperature goes down 10 degrees, how can we write it? A negative added to a negative is a “larger” negative. We add the “numbers.”
Another way to think of adding positive and negative numbers is by using red and yellow colored counters. 3 and -5 zero pairs -3 and -5 No zero pairs
MULTIPLYING INTEGERS IN ALGEBRA COUNTY
-5 TIMES 6 CAN BE WRITTEN: -5(6) -5 ·6 (-5)(6) 2(3) MEANS: • 2 GROUPS OF 3 • A 2 BY 3 ARRAY
WE CAN PICTURE 2(3): THESE ARE ALL ARRAYS
WE CAN PICTURE 2(3) AS 2 GROUPS OF 3:
Which? Group or array? 3 keys on two key rings Two stacks of three books A six-pack of cokes The chairs in church Two rows of three kitchen tiles
When we multiply: Positive X positive = + Positive X negative = - Negative X positive = - Negative X negative = +
Don’t get confused: Positive + positive = + Positive + negative = ?? Negative + positive = ?? Negative + negative = -
Negative + positive = ?? Why the question marks? -4+6 =2 (positive) -6+4 = -2 (negative)
Back to multiplication: -(-3) means: - (-3) 1 = 3 Negative 1 times negative 3 The number 1 is very important in Algebra County. Also: -(5) means: -5 which is: Negative 1 times 5 - (5) 1
Let’s work some multiplication problems: -2(5) = -10 3(-5) = -15 -4(-2) = 8 - (-6) = 6 -9(-11) = 99 - (-13) = 13