Multiplying and Dividing Integers
Multiplying and dividing integers in Grade 8 Saxon Math Course 3 teaches students the sign rules for these operations: the product or quotient of two integers with the same sign is positive, and with different signs is negative. Students apply these rules to chains of multiplications and divisions, and use them in evaluating algebraic expressions. Mastery of integer operations is essential for all subsequent algebra work.
Key Concepts
Property If the two numbers have the same sign, the answer is positive. If the two numbers have different signs, the answer is negative.
Examples $( 8) \times ( 4) = 32$ $\frac{ 20}{5} = 4$ $(6)( 7) = 42$.
Explanation Think of it like this: a friend (+) of a friend (+) is a friend (+). An enemy ( ) of an enemy ( ) is also a friend (+). But a friend (+) of an enemy ( ) is an enemy ( ). Same signs are positive pals; different signs are negative news! This helps you remember the rule for any multiplication or division problem.
Common Questions
What are the rules for multiplying integers?
Positive x positive = positive. Negative x negative = positive. Positive x negative = negative. Negative x positive = negative. Same signs give positive; different signs give negative.
What are the rules for dividing integers?
The rules are the same as for multiplication. Same signs (both positive or both negative) produce a positive quotient. Different signs produce a negative quotient.
What is (-3) x (-4)?
(-3) x (-4) = +12. Both factors are negative (same signs), so the product is positive.
What is (-12) divided by 3?
(-12) / 3 = -4. Different signs (negative and positive) give a negative quotient.
How does Saxon Math Course 3 teach integer multiplication and division?
Saxon Math Course 3 uses sign rules, number patterns, and real-world contexts to help students understand why the rules work, then provides extensive practice in applying them to expressions and equations.