Lesson 2.4Math

3. Multiplying Integers

By. Juran Seo p.70~73

Lesson 2.4MathThe Rules of Multiplying

The Signs• + , + +• + , - -• - , - +• - , + -

※ If the sign ‘-’ is even number, the answer sign is ‘+’. And if it is odd number, the answer sign is ‘-’.

※If the signs are different, the answers are negative and if the signs are the same, the answers are positive.

p.70~73

Lesson 2.4MathMultiplying Integers 1

How to multiply Integers :1-The product of two integers with the

same sign is positive(greater than 0). Ex) 4·2 = 8 / -3·(-7) = 21 :2-The product of two integers with

different signs is negative(less than 0). Ex) 4·(-2) = -8 / -3·7 = -21

p.70

Lesson 2.4MathMultiplying Integers 2

Q) A diver is exploring a coral reef. The diver’s depth is changing by -6 feet per second. If the diver started at sea level, what is the diver’s position after 10 seconds?A) Have to use the distance formula d=rt

d = rt Write the distance formula. d = -6(10) Substitute -6 for r and 10 for t. d = -60 Different signs, so product is negative.

p.70

Lesson 2.4MathMultiplication Properties

Multiplication Property of Zero The product of an integer and 0 is 0. Numbers) -4·0=0 Algebra) Any value of a, a·0=0 Identify Property of Multiplication The product of an integer and 1 is the integer. Numbers) 4(1) = 4 Algebra) For any value of a, a(1) = a

p.71

Lesson 2.4MathPractice

-1(6) = -6 Different signs, so product is negative.

-8(-2) = 16 Same sign, so product is positive.

-15(0) = 0 Product of an integer and 0 is 0.

4(-10)(-12) = -40(-12) = 480 Multiply from left to right. ｜ -2 ｜ ·5 = 2 × 5 = 10 -2(5)(-6) = (-10) × (-6) = 60 p.71~72

Absolute Value

Lesson 2.4Math

The End