Mu Lit Plying & Dividing Integers

MJ3 Ch 1.6 – Multiplying & Dividing Integers

Bellwork • Answer the following: 2. What is the rule for adding integers if the signs are the same? 3. What is the rule for adding integers if the signs are different? 4. What is the rule for subtracting integers? Reminder: To receive full credit you must write the question AND answer!

Assignment Review • None – there was no assignment yesterday….Woo hoo…

Objective • Students will multiply and divide integers

Before we begin… • Please take out your notebooks and get ready to work…. • Today’s lesson is relatively simple as the rules for multiplying and dividing are the same…

Rules • The rules for multiplying and dividing integers are the same: • If the signs are the same the answer is positive • If the signs are different the answer is negative • Here is what it looks like in symbols…

Symbols • Same Signs: Multiplication - ∙ (-) = + +∙+=+ Division - ÷ (-) = + +÷+=+

• Different Signs: Multiplication -∙+=+∙-=Division -÷+=+÷-=-

Process • I find that when multiplying or dividing integers it is easier to 1. Evaluate the numbers first 2. Then evaluate the signs • This methodology allows you to focus on the each part of the problem by breaking it down to smaller pieces and then putting all together increasing your chances of getting the correct answer… • This is a real life strategy that can be used in your everyday life…

Example #1 2(-5) = 2. Evaluate the numbers. In this case 2 time 5 = 10 3. Evaluate the signs. In this case positive times a negative is negative 2(-5) = -10

Example # 2 -8(-4) = 2. Evaluate the numbers first. In this case 8 times 4 = 32 3. Evaluate the signs. In this case negative times a negative = a positive -8(-4) = +32

Your Turn • • • • •

In the notes section of your notebook write and complete the following: 6(-8) = -2(4) = -3(-7) = (-5)2

Multiplying More Than 2 Integers • When multiplying more than 2 integers use the order of operations. That is multiply in order from left to right. • Again, use the process whereby you evaluate the numbers first, then evaluate the signs… • Here is what it looks like…

Example 2. 3. 4. 5.

-2(3)(-9) = Multiply 2 times 3 to get 6. Negative times positive is negative to get -6(-9) = Multiply 6 times 9 to get 54 Negative times a negative is positive -2(3)(-9) = 54

Your Turn •

In the notes section of your notebook write and complete the following:

• •

-4(-8)(-5) = -2(-4)2

Division •

Since the rules for multiplication and division are the same use the same process. 2. Evaluate the numbers 3. Evaluate the signs Here is what it looks like…

Example -24 ÷ 3 = 2. Evaluate the numbers. In this case 24 divide by 3 = 8 3. Evaluate the signs. In this case a negative divided by a positive = a negative -24 ÷ 3 = -8

Example -25 ÷ (-5) = 2. Evaluate the numbers. In this case 25 divided by 5 is 5 3. Evaluate the signs. In this case a negative divided by a negative is a positive -25 ÷ (-5) = +5

Your Turn •

In the notes section of your notebook write and complete the following:

-28 ÷ (-7) 36 -2 6. -40 8 • •

Summary • In the notes section of your notebook summarize the key concepts covered in today’s lesson • We discussed – The rules for multiplication and division • When the signs are the same • When the signs are different

Assignment • Text p. 617 Lesson 1.6 # 1 – 30 Reminder – I do not accept late assignments – I do not accept answers only for any assignment. – You must write the problem & show how you got your answer