Warm Up: Thursday September 3 What do you notice about these problems? 9 x 4 = 36 -9 x 4 = -36 9 x -4 = -36 -9 x -4 = 36

Warm Up: Thursday September 3* -1 ½ + 3 = - 4.75 + (- 5.30) = .25 – (- 1.45) =

Multiplying and Dividing Integers September 3, 2015

Rules When multiplying and dividing integers there are TWO rules: When multiplying or dividing integers that have the SAME sign, the answer is POSITIVE. Positive x positive = positive Negative x negative = positive +7 x +12 = +84 -6 x –5 = +30

Rules continued… Rule 2: Positive x negative = negative When multiplying or dividing integers whose signs are DIFFERENT, the answer will always be NEGATIVE. Positive x negative = negative Negative x positive = negative +8 x –4 = -32 -5 x +7 = -35

Let’s Play TIC TAC TOE

Let’s Practice! What sign would the answer have in front of the integer??? -5 x -7 = ???

POSITIVE!!!

What sign will be in front of the answer?? How about… -6 x 9 = ??? What sign will be in front of the answer??

NEGATIVE!!!

Try this one! What sign will be in front of the answer??? -81 ÷ 9 = ???

NEGATIVE!!!

Let’s solve some problems! -8 x –9 =

72

4 x 12 =

48

-45 ÷ 5 =

-9

-63 ÷ 7 =

-9

-8 x –11 =

88

Remember… When multiplying and dividing integers: Same signs = a positive Different signs = a negative

Let’s Try fractions and Decimals 2.5 x -4.1

 

(-3)(-3)(-3)

(-9.50) x 3