What happens when you multiply minus by minus?
| Example | ||
|---|---|---|
| × | Two advantages make a plus: | 3 × 2 = 6 |
| × | Two disadvantages make it an advantage: | (−3) × (−2) = 6 |
| × | negative and positive make negative: | (−3) × 2 = −6 |
| × | positive and negative make negative: | 3 × (−2) = −6 |
What happens when you multiply minus by minus?
Rule 3: A negative number multiplied by a negative number gives a positive number. Two negative numbers make a positive number, so multiplying a negative number by a negative number results in a positive number. If you look at it on the number line and walk backwards looking in the negative direction, you are moving in the positive direction.
Does multiplying the minus give any advantage?
There are two simple rules to remember: When you multiply a negative number by a positive product, the product is always negative. When you multiply two negative numbers or two positive numbers, the product is always positive. … Now we have two negative numbers, so the result is positive.
Why 2 minus plus?
When the number is positive, the + sign in front of the number is usually omitted. So 3 is effectively (+3). Adding and multiplying combinations of positive and negative numbers can be confusing, so caution is advised. Two advantages are an advantage, two disadvantages are an advantage.
How do you prove that negative numbers multiplied by negative numbers are positive?
Since multiplication is commutative, negative times positive multiplication is also negative. Similarly, we can show that a negative multiplied by a negative is positive.
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Corrolary 2.
| 0 = a + (−a) | (Axiom 4) |
|---|---|
| 0 = 0 × a + (a + (-a)) | (Axiom 5 and Axiom 2) |
| 0 = 0 × a + 0 | (Axiom 4) |
| 0 = 0 × a | (Axiom 3 and Axiom 1) |
Why multiply negative times negative times positive?
Why do you multiply two negative numbers to get a positive number? But when I say don’t eat! I say the opposite (negatively). … So two negatives make one positive, and if that’s okay with you, read no further.