Multiplying positive and negative numbers has far less rules than adding or subtracting positive and negative numbers, in fact there are only three that you’ll have to remember:
Rule 1: A positive number times a positive number gives you a positive number.
Example 1: This is the kind of multiplication you’ve been doing for years, positive numbers times positive numbers. It would look like this: 4 x 3 = 12. 4 is positive, 3 is positive, thus, 12 is positive. We know that 4 and 3 are both positive because there are no negative signs in front of them.
Rule 2: A positive number times a negative number gives you a negative number.
Example 2: This is new – for example, you might have 4 x -3. The 4 is positive, but the 3 is negative, so our answer has to be negative. Thus, we multiply the numbers together as we normally would, and then put a negative sign in front of our answer. So, 4 x -3 = -12. Please note that this also works when the negative number comes first and the positive number is second. For example, you may see it written -3 x 4, but don’t get confused. The combination of one positive and one negative number, no matter which order they come in, means your answer is going to be negative.
Rule 3: A negative number times a negative number gives you a positive number.
Example 3: This is also new—and doesn’t seem to make much sense, but it is a rule we have to follow when multiplying negative numbers together. So, for example, we may have the problem -3 x -4. Both the 3 and the 4 are negative, so we know our answer is going to be positive. Therefore, -3 x -4 = 12.
These rules also apply to division of positive and negative numbers.
|1. 2 x 3||2. -5 x 6||3. 5 x 10||4. -6 x -6||5. 7 x -8|
|6. 8 x 8||7. -3 x -9||8. -5 x 5||9. -8 x -12||10. 9 x 2|
|1. 6||2. -30||3. 50||4. 36||5. -56|
|6. 64||7. 27||8. -25||9. 96||10. 18|