How to Multiply Negative Numbers on A Calculator

Multiplying negative numbers might seem confusing at first, but it follows simple mathematical rules. This guide explains how to multiply negative numbers on a calculator, provides clear examples, and includes a built-in calculator tool to help you practice.

How to Multiply Negative Numbers

Multiplying negative numbers involves understanding the sign rules of multiplication. Here's how to do it on a calculator:

Enter the first negative number by pressing the negative sign (-) followed by the number.
Press the multiplication symbol (× or *).
Enter the second negative number by pressing the negative sign (-) followed by the number.
Press the equals (=) button to get the result.

Most scientific and graphing calculators handle negative numbers the same way as positive numbers. If you're using a basic calculator, make sure it supports negative numbers before performing the calculation.

Negative Multiplication Rules

There are two key rules to remember when multiplying negative numbers:

Negative × Negative = Positive: When you multiply two negative numbers, the result is positive.
Negative × Positive = Negative: When you multiply a negative number by a positive number, the result is negative.

Formula: a × b = c, where a and b are negative numbers, and c is the positive result.

Practical Examples

Let's look at some examples to understand how negative multiplication works:

First Number	Second Number	Result
-3	-4	12
-5	2	-10
-7	-3	21

In each case, the result follows the rules of negative multiplication. Try these examples on your calculator to see how it works.

Common Mistakes to Avoid

When multiplying negative numbers, it's easy to make a few common mistakes:

Forgetting the negative sign: Always remember to include the negative sign when entering negative numbers.
Incorrectly applying the rules: Remember that two negatives make a positive, and a negative and a positive make a negative.
Calculator limitations: Some basic calculators may not support negative numbers. If you encounter issues, try using a scientific or graphing calculator.

FAQ

Can I multiply negative numbers on any calculator?

Most scientific and graphing calculators support negative numbers. Basic calculators may not, so check your calculator's capabilities before performing the calculation.

What happens if I multiply a negative number by zero?

Multiplying any number by zero results in zero. So, -5 × 0 = 0.

How do I multiply negative decimals on a calculator?

Enter the negative decimal the same way you would enter a negative whole number, using the negative sign followed by the decimal value.

Is there a difference between multiplying negative numbers and positive numbers?

Yes, the sign rules are different. Negative × Negative = Positive, while Negative × Positive = Negative.