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Mathematics » Introducing Integers » Multiply and Divide Integers

# Key Concepts

This is a lesson from the tutorial, Introducing Integers and we encourage you to log in or register before you continue, so that you can track your progress.

## Key Concepts

• Multiplication of Signed Numbers
• To determine the sign of the product of two signed numbers:
Same SignsProduct
Two positives

Two negatives

Positive

Positive

Different SignsProduct
Positive • negative

Negative • positive

Negative

Negative

• Division of Signed Numbers
• To determine the sign of the quotient of two signed numbers:
Same SignsQuotient
Two positives

Two negatives

Positive

Positive

Different SignsQuotient
Positive • negative

Negative • Positive

Negative

Negative

• Multiplication by $$-1$$
• Multiplying a number by $$-1$$ gives its opposite: $$-1a=-a$$
• Division by $$-1$$
• Dividing a number by $$-1$$ gives its opposite: $$a÷\left(-1\right)=\mathit{\text{−a}}$$