Reviewing Integers

If you stay seven weeks and owe $13 per week for rent, how much is

your total bill? Explain your reasoning. How can you check

yourself?

https://www.youtube.com/watch?v=xkbQDEXJy2k

Adding Integers

There are four rules for adding integers. See if your group can write four rules using only +’s

and –’s and =‘s.I will start you on the next slide

if needed shortly.

The 4 Rules of Addition

(1) + + + = +(2) - + - = -

(3) + + - = +(4) - + + = -

Real Problems

(1) 9 + 7 = 16(2) -4 + (-5) = -9

(3) 15 + (-11) = 4(4) -8 + 5 = -3

Subtracting Integers(1)17 – 14 = 3(2) 14 -17 = -3(3) -13 – 23 = -36(4)23- (-13) = 36(5)-14 – (-7) = -7(6) -7 – (-14) = 7Write these sample problems down in your

notes and see if the rules for addition apply to subtraction.

NO THEY DO NOT!So what can we do?

USE A NUMBER LINE IF YOU CANNOT SUBTRACT INTEGERSI will demonstrate with the following problems.

(1)7 – 9(2)-3 – 4

(3)-6 – (-7)

Multiplying and Dividing IntegersBased on the following information, write as few

rules as possible regarding multiplying and dividing integers.

(1) 3 ● 4 = 12 (5) 12/4 = 3(2) 3 ● (-4) = -12 (6) 12 ÷ (-4) = -3(3) -3 ● 4 = -12 (7) -12 ÷ 4 = -3(4) (-3) ● (-4) = 12 (8) -12/-4 = 3

You should have written ONLY TWO RULES!(1) If both integers have the same sign, the result

will always be positive.(2) If the signs of the integers are different, the

result will always be negative.

Notebook Examples• (1) 8 + (-15)• (2) 4 – (-5)• (3) -7 + 21• (4) -5 – 3• (5) (-6)(-8)• (6) 11(-15)• (7) -56 ÷ 8• (8) 12 • 6• (9) (-3) + (-6)• (10) -120• -10

• Answers• (1) -7• (2) 9• (3) 14• (4) -8• (5) 48• (6) -165• (7) -7• (8) 72• (9) -9• (10) 12