Long Division Using Standard Algorithm Adapted from 21

Long Division: Using Standard Algorithm Adapted from 21 st Century Lessons 1

Objectives • Students will be able to indentify the parts of division problems in various forms. • Students will be able to explain and apply multi-digit division using standard algorithm. • Students will be able to discuss long division using correct vocabulary. 2

Vocabulary • Algorithm: A formula or set of steps for solving a problem. • Division: Splitting of large numbers into equal groups of smaller numbers. • Dividend: Number being divided. • Divisor: Number you are dividing by. • Quotient: Answer to a division problem.

Vocabulary Video http: //youtube. com/watch? v=0 RCj. WZe 0 q. BQ

On a school field trip, your class Warm Up followed a treasure map and found a buried treasure! Imagine that your class has 25 students total, and that there were 1000 gold coins in the treasure chest. How many coins does each student get? Express your answer in three different ways. 5

Warm Up We found 1000 gold coins, and need to divide them equally between the 25 students in our class. Express the problem in three ways. _____ 1000 = 1000 ÷ 25 = 25) 1000 25 6

Warm Up So how many coins does each student get? 1000 = 25 1000 ÷ 25 = _____ 25) 1000 We’ll check back on this problem in a little while! 7

With your partner, list the three ways to express the clam’s division problem. 8

With your partner, list the three ways to express the clam’s division problem: FRACTION 9 NUMBER SENTENCE LONG DIVISION ALGORITHM

The Steps to Long Division Video http: //www. youtube. com/watch? v=0 u. Ziqk_Zdc. A

How many steps are there in the long division algorithm? 11

How many steps are there? 12

Let’s apply the steps to long division to a new problem: 84 ÷ 6 = ? 13

Explore DIVIDE MULTIPLY SUBTRACT BRING DOWN 14

Set up the problem: 84 ÷ 6 = ? in the long division algorithm looks like which of the options below? CHOICE A CHOICE B ? 84 6)? 84 ? )6 6) 84 6 =? 84 84 = ? 6 ✗ 15 CHOICE C ✗

STEP ONE: DIVIDE 1 8÷ 6= Follow along with the Guided Practice Worksheet! 16 1 We divide the dividend by the divisor.

STEP TWO: MULTIPLY 6 6 x 1= We multiply 17 6

STEP FOUR: BRING DOWN 4 We bring the 4 down 18

STEP THREE: SUBTRACT 2 8– 6= We subtract 19 2

NOW WHAT? ? ? 20

STEP ONE: DIVIDE 4 24 ÷ 6 = We divide 21 4

STEP TWO: MULTIPLY 24 6 X 4= We multiply 22 24

STEP THREE: SUBTRACT 0 24 – 24 = We subtract 23 0

STEP FOUR: BRING DOWN There is no number to bring down – we’re almost DONE! 24

Don’t forget to check your answer! The opposite of 84 ÷ 6 = 14 is 6 X 14 = 25

Checking your answer 14 x 6 84 26

Practice 1 Let’s try one more problem – try it alone and we’ll review it together! 144 ÷ 12 = ? What do these number sentences look like in the long division algorithm? 27 144 =? 12) 144

Practice 1 STEP ONE: DIVIDE 1 14 ÷ 12 = 1 What are we dividing? We are dividing the dividend by the divisor. 28

Practice 1 STEP TWO: MULTIPLY 12 12 X 1 = We multiply 29 12

Practice 1 STEP THREE: SUBTRACT 2 14 – 12 = We subtract 30 2

Practice 1 STEP FOUR: BRING DOWN 4 We bring down 31

Practice 1 NOW WHAT? ? ? 32

Practice 1 STEP ONE: DIVIDE 2 24 ÷ 12 = 2 We divide the dividend by the divisor. 33

Practice 1 STEP TWO: MULTIPLY 24 12 x 2 = We multiply 34 24

Practice 1 STEP THREE: SUBTRACT 24 - 24 = 0 35 We subtract 0

Practice 1 STEP FOUR: BRING DOWN There is no number to bring down – we’re almost done! 36

Practice 1 Don’t forget to check your answer! The opposite of 144 ÷ 12 = 12 is 12 X 12 = 37

Practice 1 Checking your answer 12 x 12 144 38

Exit Ticket So how many coins does each student get? 1000 = 25 1000 ÷ 25 = _____ 25) 1000 Show your work using the long division algorithm. 39

Exit Ticket So how many coins does each student get? Each student gets gold coins! 40 40

Summary 1. How many steps are there to the long division algorithm? What are they? 2. What is the trick the video taught us to remember the steps? 3. Is there anything confusing about using the long division algorithm? 41

Credits Original lesson designed by Catherine Murphy & Sarah Kelly. 21 st Century Lessons. Funded by the American Federation of Teachers. Retrieved from http: //www. sharemylesson. com 42