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Name __________________________ Learning Objective Today, we will multiply decimal numbers. CFU What are we going to do today? Activate (or provide) Prior Knowledge Multiplication is repeated addition of equal groups. • A factor is a number used in a multiplication problem. • The product is the answer to a multiplication problem. 3 factors 4 12 product Solve the multiplication problems on your whiteboards. 1. 2 2 1 5 4 8 6 0 2. 1 1 2 6 3 3 7 8 CFU Students, you already know how to multiply with whole numbers. Today, we will use these skills to multiply decimal numbers. DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Concept Development To multiply is to do repeated addition of equal groups. A decimal number represents a whole number and a part of a whole number separated by a decimal point. To multiply decimal numbers: • Decimal numbers do not need to be lined up by place value. • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Multiplying Decimal Numbers Jimmy receives $2.15 every day for allowance. How much will he have if he saves his money for five days? 2.15 2.15 2.15 2.15 + 2.15 10.75 .1 1 0 .7 2 2 Look at the multiplication problem on the right. How many decimal places would there be on the right in the product? B 2 5 5 Jimmy will have $10.75 if he saves his allowance for five days. CFU On your whiteboard, write a decimal number. How do you know it is a decimal number? A 1 5 C 3 D 4 Between which two digits would the decimal point be placed in the product? In your own words, what is the main difference between multiplying whole numbers and decimal numbers? The main difference is _____________. DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] . . . 4 1 3 2 2 3 6 8 1 8 Flashcards Decimal Point Placement 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Skill Development/Guided Practice To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Multiply Decimal Numbers . . 2 1 5 5 1 0 7 5 Multiply decimal numbers. Step #1: Multiply the bottom factor with each digit of the top factor. (regroup if needed) a. Add regrouped numbers, if any. Step #2: Count the total number of decimal places in the two factors. a. Place a decimal in the product that many places to the left. 1. 2 . . 2. 1 1 4 7 9 8 4. 1 . . . . 3 1 2 8 9 6 5. 6 2 0 4 2 4 8 . . 0 decimal places 2 decimal places . . 1 1 7 3 5 8 6 5 6. 3 1 2 6 6 7 5 6 3. 2 decimal places 4 8 7 0 6 5 2 2 . . CFU (#2) How did I/you count the total number of decimal places in the two factors? (#2a) How did I/you place a decimal in the product that many places to the left? DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Skill Development/Guided Practice (continued) To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Multiply Decimal Numbers . . 2 1 5 5 1 0 7 5 Multiply decimal numbers. Step #1: Multiply the bottom factor with each digit of the top factor. (regroup if needed) a. Add regrouped numbers, if any. Step #2: Count the total number of decimal places in the two factors. a. Place a decimal in the product that many places to the left. 7. 2 8. . . 11. . . . 6 2 0 4 2 4 8 . . . 1 4 6 7 1 0 0 2 0 9 3 4 2 2 decimal places 4 . . 8 7 0 6 5 2 2 . 12. 1 0 decimal places 9. 7 3 5 2 2 14 7 0 4 5 8 1 1 3 1 7 4 3 3 10. . . 1 2 decimal places . . . 1 2 1 2 4 6 3 0 0 4 0 9 8 5 2 CFU (#2) How did I/you count the total number of decimal places in the two factors? (#2a) How did I/you place a decimal in the product that many places to the left? DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Relevance To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. 1. Multiplying decimal numbers will help you determine the cost of multiple items. $0.51 for 1 pencil sharpener. $0.51 3 =$1.53 $1.53 for 3 pencil sharpeners. 2. Multiplying decimal numbers will help you convert measurement. One inch equals 2.54 centimeters. 2.54 A box is 14 inches long, how x 14 35.56 many centimeters long is it? The box is 35.56 centimeters long. 3. Multiplying decimal numbers will help you do well on tests. CFU Does anyone else have another reason why it is relevant to multiply decimal numbers? (pair-share) Why is it relevant to multiply decimal numbers? You may give me one of my reasons or one of your own. Which reason is most relevant to you? Why? 5th Grade Number Sense 2.1 (7Q) DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Multiply Decimal Numbers Skill Closure Multiply decimal numbers. . . 2 1 5 5 1 0 7 5 Step #1: Multiply the bottom factor with each digit of the top factor. (regroup if needed) a. Add regrouped numbers, if any. Step #2: Count the total number of decimal places in the two factors. a. Place a decimal in the product that many places to the left. 1. 2 . . 2. 2 6 4 1 0 4 1 2 decimal places 0 decimal places 2 decimal places .. 3 2 0 7 2 2 4 . Concept Closure Look at the multiplication problem below. Where would you place the decimal points in the factors if the product was 1.6892? Explain your answer. Hint: There are multiple answers. 1 0 3 1 6 4 __________________________________________________________________________________________________________ __________________________________________________________________________________________________________ __________________________________________________________________________________________________________ What did you learn today about multiplying decimal numbers? Day 1 ________________________________________________________________________________________________ Day 2 ________________________________________________________________________________________________ DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Name _____________________________ Independent Practice To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Multiply Decimal Numbers . . 2 1 5 5 1 0 7 5 Multiply decimal numbers. Step #1: Multiply the bottom factor with each digit of the top factor. (regroup if needed) a. Add regrouped numbers, if any. Step #2: Count the total number of decimal places in the two factors. a. Place a decimal in the product that many places to the left. 1. 4 2. . . . . 5. 1 . . 3 2 7 2 5 4 6 4 3 5 2 4 DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 2 decimal places 4 4 2 9 0 5 1 4 5 2 3 5 x 8 18 8 0 4. 0 decimal places 3. 2 3 6 8 2 8 8 2 decimal places . . 6. 2 . . 6 3 0 8 5 0 4 . 2 . 2 1 6 5 4 2 0 5 3 2 7 1 0 . . 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Name _____________________________ Periodic Review 1 To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Multiply Decimal Numbers . . 2 1 5 5 1 0 7 5 Multiply decimal numbers. Step #1: Multiply the bottom factor with each digit of the top factor. (regroup if needed) a. Add regrouped numbers, if any. Step #2: Count the total number of decimal places in the two factors. a. Place a decimal in the product that many places to the left. 1. 2. 1 . . 4. . . 5 8 1 1 3 17 4 3 3 DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 2 decimal places . . 4 2 8 7 0 6 5 2 2 4 3 9 3 1 3 1 7 5. 2 0 decimal places 3. 1 3 6 2 7 2 2 decimal places . . 6. 1 . . 3 2 0 8 2 5 6 . 5 . 1 4 7 2 1 0 8 3 7 7 6 8 . . 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Name _____________________________ Periodic Review 2 To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Multiply Decimal Numbers . . 2 1 5 5 1 0 7 5 Multiply decimal numbers. Step #1: Multiply the bottom factor with each digit of the top factor. (regroup if needed) a. Add regrouped numbers, if any. Step #2: Count the total number of decimal places in the two factors. a. Place a decimal in the product that many places to the left. 1. 2. 3 . . 4. . . 1 . . 1 DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 7 2 0 7 5 0 4 4 7 2 5 23 6 0 . . 6. 2 4 9 2 4 6 29 5 4 4 2 decimal places 1 5. 5 0 decimal places 3. 3 3 6 5 1 8 0 2 decimal places 1 . . 3 4 0 3 1 0 2 . 5 . 6 3 3 5 7 4 0 9 3 2 1 6 6 . . 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Name _____________________________ Periodic Review 3 To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Multiply Decimal Numbers . . 2 1 5 5 1 0 7 5 Multiply decimal numbers. Step #1: Multiply the bottom factor with each digit of the top factor. (regroup if needed) a. Add regrouped numbers, if any. Step #2: Count the total number of decimal places in the two factors. a. Place a decimal in the product that many places to the left. 1. 2. . . 4. . . 2 . . 1 DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 5 2 0 7 3 6 4 2 5 2 7 1 7 6 4 .. 6. 1 6 6 4 3 6 3 9 8 5 8 2 decimal places 1 5. 3 0 decimal places 3. 3 5 3 3 1 5 9 2 decimal places 2 . . 4 3 0 7 3 0 1 . . 2 4 4 1 3 7 0 6 2 4 8 2 2 . . 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Flashcards (Decimal Point Placement) To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Teacher with CFU If the product is 231.15, where would the decimal points be in the factors? . 6 .7 3 4 5 How did I know where to put the decimal point for each factor? DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Flashcards (Decimal Point Placement) To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Student with CFU If the product is 10.528, where would the decimal points be in the factors? . 2 2 4 . 4 7 How did you know where to put the decimal point for each factor? DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Flashcards (Decimal Point Placement) To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Student If the product is 0.4504, where would the decimal points be in the factors? .5 DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 6 3 .8 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Flashcards (Decimal Point Placement) To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Student If the product is .52241, where would the decimal points be in the factors? .1 . 1 9 4 3 9 DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Flashcards (Decimal Point Placement) To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Student If the product is 41.28, where would the decimal points be in the factors? . . 9 6 4 3 DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only. Flashcards (Decimal Point Placement) To multiply decimal numbers: • The number of decimal places in the product is equal to the total number of decimal places in the numbers being multiplied. Student with CFU If the product is 1.6, where would the decimal points be in the factors? 8 2 . How did you know where to put the decimal point for each factor? Back to Skill Development DataWORKS Educational Research (800) 495-1550 • www.dataworks-ed.com ©2012 All rights reserved. Comments? [email protected] 5th Grade Number Sense 2.1 (7Q) Add, subtract, multiply, and divide with decimals; add with negative integers; subtract positive integers from negative integers; and verify the reasonableness of the results. Lesson to be used by EDI-trained teachers only.