# Math Journal 8-13-14 Find the perimeter of the trapezoid: 4x ft 3x ft 60x in.

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Math Journal 8-13-14 Find the perimeter of the trapezoid: 4x ft 3x ft 60x in

UNIT 1 DAY 3: EVALUATING EXPRESSIONS WITH MULTIPLYING AND DIVIDING INTEGERS Essential Questions: What are the rules for multiplying and dividing integers? How do you substitute a number for a variable?

Product: the answer obtained by multiplying two or more quantities. Factor: the numbers and variables that are multiplied in an expression. Quotient: the answer obtained by dividing two or more quantities. Vocabulary

Multiplying and Dividing Integers To figure out the signs when multiplying or dividing integers, use the following rules: Same Signs: Positive Different Signs: Negative If you have more than two negative factors… Even # of negatives = positive Odd # of negatives = negative

Example 1 a)-8(2)b) -5(-7) c) 12(9)d) (1/2)(-18) -1635 108-9

Example 2 a)b) c) d) 6-10 -97

Evaluating Expressions To evaluate an expression: 1) Substitute each variable with the given number. 2) Simplify the expression to a single value.

Example 3 Evaluate the following expressions when a = 12, b = -3, and c = 24. a)6/bb) a/b c)c/-bd)b(c/a) 6/-3 -2 12/-3 -4 24/3 8 -3(24/12) -3(2) -6

Example 4 The plane’s height above the ground (in thousands of feet) equals the distance from the airport (in miles) that a plane should begin descending divided by 3. height = distance/3 If a plane is 30 miles from the airport when the pilot begins to land the plane, what is the plane’s height above ground in thousands of feet? h The plane is 10 thousand feet above the ground. height = 30/3

Summary Essential Questions: What are the rules for multiplying and dividing integers? How do you substitute a number for a variable? Use 1 minute to write 2 sentences answering the essential questions.

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