Multiplying 3-Digit Whole Numbers by Decimal Tenths Lesson PDF

Tips for Teachers! The parts of the lesson are explained below: Getting Started An activity to activate prior background knowledge (20 minutes)  Print and handout both sheets  Ask students if they noticed the pattern in the multiplication questions at the top of th...

Tips for Teachers! The parts of the lesson are explained below: Getting Started An activity to activate prior background knowledge (20 minutes)  Print and handout both sheets  Ask students if they noticed the pattern in the multiplication questions at the top of the page  Explain that the number of digits to the right of the decimal point in the question has to equal the amount of digits to the right of the decimal point in the answer and this will help them determine where to place the decimal point after multiplying  Go over each strategy, demonstrate a few  On the next page, have students place the decimal point in the correct spot in each answer  Next, model how to use each strategy by filling in the blanks or have students volunteer to fill in the blanks  Take up the questions Working On It! A cooperative task (20 minutes)  Students could work alone, in partners, or small groups  Print and hand out the Hungry Hippo Challenge along with a paper clip  If possible, laminate the Game so it can be used multiple times using dry erase markers  Model how to play  Have students perform their calculations in a notebook or piece of paper  You could let students use a calculator to check each others calculations  Circulate and check for understanding Exit Ticket An independent task (20 minutes)  Hand out for students to complete individually  Collect and observe for assessment © 2021 Blue Sky Scholastics  Learning Goal: To multiply 3 digit whole numbers by decimal tenths Do you notice a pattern below? 102 10.2 1.02 1.02 x2 x2 x 2 x0.2 204 20.4 2.04.204 The number of digits to the right of the decimal in our question Partial Products = Multiplication Strategies The number of digits to the right of the decimal in our answer Decompose 1. Ignore the decimal and treat the value like a whole number. 1. Break your decimal number into a whole number and 0.1 142 x 0.2 142 x 2 231 x 0.2 231 x 2 x 0.1 2. Break your whole number into parts that we can multiply by 2. 2. Multiply your number by the whole number first. 100 x 2 = 200 231 x 2 = 462 142 40 x 2 = 80 3. Next, multiply your product by the 0.1. Note: When you multiply 2x2=+ 4 be 0.1, remember that the decimal moves one space to the left. 3. Now add in your decimal. =284 462 x 0.1 = 46.2 142 x 0.2 = 28.4 } } 1 decimal number in our question = 1 decimal number in our answer. Area Model (Arrays) Standard Algorithm (Stacking) 1. Ignore the decimal and treat the value like a whole number. 1. Multiply 3 with the 2. We can't have more 3. Multiply 3 with the 4. Multiply 3 with the digit in the ones place than 10 in a place value digit in the tens place digit in the hundreds 142 x 0.2 142 x 2 value. (3 x 5 = 15) so we move the 1 to value. Add the 1 to the place value. (3 x 2 = 6) the tens place value. product (3 x 2 + 1 = 7) 2. Break your 3 digit whole number into friendly numbers that are easy to 1 +1 multiple by. 225 225 225 225 142 x x x 4. Add up x 0.3 x 0.3 x 0.3 x 0.3 1 3. Multiply 100 20 20 2 your totals. = 15 = 5 = 75 = 675 the rows and 200 5. Now figure out where to place the decimal number. The number of digits to the right of the 2 columns 100 x 2 20 x 2 20 x 2 2 x 2 40 decimal in your question has to equal the number of digits to the right of the decimal in your answer. 225 = 200 = 4 40 = 40 = 40 + 4 284 1 number to the right of 5. Now add your decimal back in. x 0.3 the decimal in the question so 1 number has 142 x 0.2 = 28.4 =67.5 to be to the right of the } } 1 decimal number in our question = 1 decimal number in our answer. decimal in the answer © 2021 Blue Sky Scholastics  Learning Goal: To multiply 3 digit whole numbers by decimal tenths Instructions: Place the decimal numbers in the correct spot in the answers. 1) 314 x 0.2 = 628 5) 182 x 0.4 = 728 2) 185 x 0.5 = 925 6) 293 x 0.2 = 586 3) 221 x 0.4 = 884 7) 333 x 0.5 = 1665 4) 213 x 0.3 = 693 8) 614 x 0.2 = 1228 NOW YOU TRY! Partial Products Decompose 1. Ignore the decimal and treat the value like a whole number. 1. Break your decimal number into a whole number and 0.1 123 x 0.3 123 x 3 451 x 0.2 451 x 2 x 0.1 2. Break your whole number into parts that we can multiply by 2. 2. Multiply your number by the whole number first. 100 x 3 = 200 451 x 2 = 284 123 40 x 3 = 80 3. Next, multiply your product by the 0.1. Note: When you multiply 2x3= 4 + be 0.1, remember that the decimal moves one space to the left. 3. Now add in your decimal. =284 284 x 0.1 = 123 x 0.3 = 28.4 } } 1 decimal number in our question = 1 decimal number in our answer. Area Model (Arrays) Standard Algorithm (Stacking) 1. Ignore the decimal and treat the value like a whole number. 1. Multiply 4 with the 2. We can't have more 3. Multiply 4 with the 4. Multiply 4 with the digit in the ones place than 10 in a place value digit in the tens place digit in the hundreds 214 x 0.5 214 x 5 value. (4 x 3 = ?) so we move the extra value. Add the extra place value. (4 x 1) digit to the tens place digit to the product. value. 2. Break your 3 digit whole number into friendly numbers that are easy to 1 + multiple by. 123 123 123 123 214 x x x 4. Add up x 0.4 x 0.4 x 0.4 x 0.4 3. Multiply 100 20 20 2 your totals. = = 5 = 75 = 675 the rows and 200 5. Now figure out where to place the decimal number. The number of digits to the right of the 5 = 200 columns 100 x 5 20 x 5 20 x 5 2 x 5 40 decimal in your question has to equal the number of digits to the right of the decimal in your answer. 123 40 = 40 = 40 = 4 + 4 + 1 number to the right of 5. Now add your decimal back in. = 284 x 0.4 the decimal in the question so 1 number has 214 x 0.5 = 28.4.5 to be to the right of the } } 1 decimal number in our question = 1 decimal number in our answer. decimal in the answer © 2021 Blue Sky Scholastics  Learning Goal: To multiply 3 digit whole numbers by decimal tenths Instructions: Place the decimal numbers in the correct spot in the answers. 1) 314 x 0.2 = 62.8 5) 182 x 0.4 = 72.8 2) 185 x 0.5 = 92.5 6) 293 x 0.2 = 58.6 3) 221 x 0.4 = 88.4 7) 333 x 0.5 = 166.5 4) 213 x 0.3 = 69.3 8) 614 x 0.2 = 122.8 NOW YOU TRY! Partial Products Decompose 1. Ignore the decimal and treat the value like a whole number. 1. Break your decimal number into a whole number and 0.1 123 x 0.3 123 x 3 451 x 0.2 451 x 2 x 0.1 2. Break your whole number into parts that we can multiply by 2. 2. Multiply your number by the whole number first. 100 100 x 3 = 200 300 451 x 2 = 284 902 123 40 20 x 3 = 80 60 3. Next, multiply your product by the 0.1. Note: When you multiply 2 3 x3= 4 + 9 be 0.1, remember that the decimal moves one space to the left. 3. Now add in your decimal. =284 369 284 902 x 0.1 = 90.2 123 x 0.3 = 28.4 36.9 } } 1 decimal number in our question = 1 decimal number in our answer. Area Model (Arrays) Standard Algorithm (Stacking) 1. Ignore the decimal and treat the value like a whole number. 1. Multiply 4 with the 2. We can't have more 3. Multiply 4 with the 4. Multiply 4 with the digit in the ones place than 10 in a place value digit in the tens place digit in the hundreds 214 x 0.5 214 x 5 value. (4 x 3 = ?) so we move the extra value. Add the extra place value. (4 x 1) digit to the tens place digit to the product. value. 2. Break your 3 digit whole number into friendly numbers that are easy to 11 +1 multiple by. 123 123 123 123 214 x x x 4. Add up x 0.4 x 0.4 x 0.4 x 0.4 3. Multiply 100 100 20 100 20 10 42 your totals. = 12 = 5 2 = 975 2 = 4 675 9 2 the rows and 500 200 5. Now figure out where to place the decimal number. The number of digits to the right of the 5 = 200 100 x 5 100 columns 100 20 x 5 10 20 x 5 4 2 x 5 500 40 decimal in your question has to equal the number of digits to the right of the decimal in your answer. 126 40 50 500 = 500 40 = 50 40 = 4 20 + 20 4 + 1 number to the right of 5. Now add your decimal back in. = 1070 284 x 0.4 the decimal in the question so 1 number has 1070 214 x 0.5 = 28.4 4 9.52 to be to the right of the } } 1 decimal number in our question = 1 decimal number in our answer. decimal in the answer © 2021 Blue Sky Scholastics  Learning Goal: To multiply 3 digit whole numbers by decimal tenths Hungry Hippo Challenge 231 kg Instructions: The owners of the hippos below x 0.5 have decided to have a contest to 125 kg 162 kg see whose hippo could eat the most. To play, a player will spin x 0.4 x 0.1 both wheels, multiply the numbers that are landed on, and write the 256 kg 311 kg product in the chart below. After each player has spun 10 times, both x 0.2 x 0.3 players will add up their 10 143 kg recorded weights. The player whose hippo has ate the most x 0.6 kilograms will win the game! Player 1 Player 2 + + = kg = kg © 2021 Blue Sky Scholastics  Learning Goal: To multiply 3 digit whole numbers by decimal tenths Instructions: Solve each answer below. Place the letter of the question over the matching answer. C 945 x 0.2 S 852 x 0.4 N 713 x 0.3 T 326 X 0.3 W 766 x 0.3 O 679 x 0.5 B 655 x 0.6 E 293 x 0.5 A 391 x 0.9 T 906 X 0.4 O 719 x 0.7 T 385 x 0.8 H 501 x 0.2 A 386 x 0.7 E 464 x 0.5 S 637 x 0.2 M 953 x 0.8 O 469 x 0.9 Why did the whale blush? 339.5 213.9 422.1 270.2 503.3 127.4 393.0 308.0 189.0 146.5 229.8 762.4 351.9 340.8 232.0 362.4 97.8 100.2 © 2021 Blue Sky Scholastics  Learning Goal: To multiply 3 digit whole numbers by decimal tenths Instructions: Solve each answer below. Place the letter of the question over the matching answer. C 189.0 S 340.8 N 213.9 945 x 0.2 852 x 0.4 713 x 0.3 T 97.8 W 229.8 O 339.5 326 X 0.3 766 x 0.3 679 x 0.5 B 393.0 E 146.5 A 351.9 655 x 0.6 293 x 0.5 391 x 0.9 T 362.4 O 503.3 T 308.0 906 X 0.4 719 x 0.7 385 x 0.8 H 100.2 A 270.2 E 232.0 501 x 0.2 386 x 0.7 464 x 0.5 S 127.4 M 762.4 O 422.1 637 x 0.2 953 x 0.8 469 x 0.9 Why did the whale blush? S A W T H E O C E A N S B OT T O M 339.5 213.9 422.1 270.2 503.3 127.4 393.0 308.0 189.0 146.5 229.8 762.4 351.9 340.8 232.0 362.4 97.8 100.2 © 2021 Blue Sky Scholastics  Thank You! _______________ You may also like… er/7775 5.html Be the first to know about new products and receive freebies and discounts by clicking FOLLOW MY TPT STORE. Click here to check out similar products from Blue Sky Scholastics  _____________ Terms of Use Thank you for your purchase! By purchasing this resource, you are agreeing that the contents are the property of Blue Sky Scholastics and are licensed for individual use in one classroom. 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