ACT Math : How to multiply negative numbers
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Example Questions
Example Question #9 : Arithmetic
If a = –2 and b = –3, then evaluate a3 + b2
8
5
1
17
9
1
When multiplying negative numbers, we get a negative answer if there are an odd number of negative numbers being multiplied. We get a positive answer if there are an even number of negative numbers being multiplied.
a3 + b2 becomes (–2)3 + (–3)2 which equals –8 + 9 = 1
Example Question #1 : How To Multiply Negative Numbers
Evaluate:
–3 * –7
21
–21
4
10
–10
21
Multiplying a negative number and another negative number makes the product positive.
Example Question #1 : How To Multiply Negative Numbers
Evaluate.
Multiplying a negative and a positive number creates a negative product:
Example Question #2 : How To Multiply Negative Numbers
Solve.
A negative number multiplied by a positive number will always be negative.
Example Question #2 : How To Multiply Negative Numbers
Evaluate 3x3 + x2 if x = –2
14
28
–20
–22
–20
When multiplying a negative number an odd number of times, the answer is negative. When multiplying a negative number an even number of times, the answer is positive. Order of operations also applies: Parentheses, Exponents, Multiplication and Division, Addition and Subtraction, from left to right. A mnemonic to remember the order of operations is “Please excuse my dear Aunt Sally.”
3(–2)3 + (–2)2
= 3(–8) + (4)
= –24 + 4
= –20
Example Question #1 : How To Multiply Negative Numbers
Simplify the following expression: (–4)(2)(–1)(–3)
–24
24
12
–16
–24
First, we multiply –4 and 2. A negative and a positive number multiplied together give us a negative number, so (–4)(2) = –8. A negative times a negative is a positive so (–8)(–1) = 8. (8)(–3) = –24.
Example Question #3 : How To Multiply Negative Numbers
Evaluate the following:
Two odd numbers multiplied always result in an even number. Simply multiple the two as though they were even. Thus
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