Develop Skills and Strategies Lesson 3 Part 1: Introduction CCSS 4.NBT.B.4 Add and Subtract Whole Numbers In this lesson, you will use place-value understanding and basic facts to add and subtract numbers. Take a look at this problem. Katie has 3,437 stamps in her collection and Steve has 942 stamps in his collection. How many stamps do Katie and Steve have in all? Explore It Use the math you already know to solve the problem. What operation can you use to find the number of stamps Katie and Steve have in all? What is the sum of the digits in the ones place? What is the sum of the digits in the tens place? What is the sum of the digits in the hundreds place? What is the sum of the digits in the thousands place? Which place value has a sum of more than 10? Explain how you can find the number of stamps Katie and Steve have in all. 16 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Part 1: Introduction Lesson 3 Find Out More There are many different ways to add numbers. For example, you can use base-ten blocks, or place-value drawings. You can break numbers apart and add the parts. When you add numbers in the thousands, some methods are more convenient than others. You can stack the numbers and line up place values. Here is one way to find the sum on page 16. Add from right to left. Add the ones, add the tens, add the hundreds, and then add the thousands. 3,437 1 942 9 70 1,300 1 3,000 7 ones 1 2 ones 5 9 ones 3 tens 1 4 tens 5 7 tens 4 hundreds 1 9 hundreds 5 13 hundreds or 1 thousand 1 3 hundreds 3 thousands 4,379 Katie and Steve have 4,379 stamps in all. Reflect 1 Solve the problem above by adding left to right: thousands, hundreds, tens, ones. Describe how the methods are alike and how they are different. 3,437 1 942 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. 17 Part 2: Modeled Instruction Lesson 3 Read the problem below. Then explore different ways to add four-digit numbers. At a fair, 4,657 ride tickets were sold on Saturday and 3,804 were sold on Sunday. How many tickets were sold in all during those two days? Model It You can use place value to add. Add ones to ones, tens to tens, hundreds to hundreds, thousands to thousands. 4,657 1 3,804 11 50 1,400 1 7,000 7 ones 1 4 ones 5 11 ones or 1 ten 1 1 one 5 tens 1 0 tens 5 5 tens 6 hundreds 1 8 hundreds 5 14 hundreds or 1 thousand 1 4 hundreds 4 thousands 1 3 thousands 5 7 thousands 8,461 Model It You can record the sums by showing regrouping above the problem. 1 4,657 1 3,804 1 7 ones 1 4 ones 5 11 ones or 1 ten 1 1 one 1 4,657 1 3,804 61 1 1 ten 1 5 tens 1 0 tens 5 6 tens 1 4,657 1 3,804 461 1 6 hundreds 1 8 hundreds 5 14 hundreds or 1 thousand 1 4 hundreds 1 4,657 1 3,804 18 8,461 1 thousand 1 4 thousands 1 3 thousands 5 8 thousands L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Part 2: Guided Instruction Lesson 3 Connect It Now you will see how to solve the problem by showing all the steps at once. 2 Here is what the second model looks like showing all the steps at once. 1 1 4,657 1 3,804 8,461 The sum of the ones values is 11. Where do you see the 11 in the equation above? 3 The sum of the hundreds values is 1,400. Where do you see the 1,400 in the equation above? 4 Why are there numbers above the tens place and above the thousands place? 5 Explain how to add two four-digit numbers if you need to regroup tens and hundreds. Try It Use what you just learned to solve this problem. Show your work two ways on a separate sheet of paper. 6 A video game company sold 5,680 copies of its new game on the first day and 3,235 copies on the second day. In just two days, how many copies of the game did the company sell? L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. 19 Part 3: Modeled Instruction Lesson 3 Read the problem below. Then explore different ways to subtract numbers. Last week, Mr. Diaz flew 4,002 miles for work. This week, he flew 2,153 miles. How many more miles did Mr. Diaz fly last week than this week? Model It You can use place value to subtract 4,002 2 2,153. You can’t subtract 3 from 2, so you need to borrow and regroup to subtract the ones digits. Write 4,002 in a place-value chart. You can’t borrow from the tens or hundreds places, so borrow from the thousands place. Keep regrouping until you can subtract. Thousands Hundreds Tens 4 0 0 Ones 2 3 10 0 2 4 thousands 5 3 thousands 1 10 hundreds 3 9 10 2 10 hundreds 5 9 hundreds 1 10 tens 3 9 9 10 1 2 5 12 10 tens 5 9 tens 1 10 ones Now you can subtract. Thousands Hundreds Tens 3 9 9 2 2 1 5 1 8 4 20 Ones 12 3 9 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Part 3: Guided Instruction Lesson 3 Connect It Now you will solve the problem from the previous page by showing regrouping above the problem. 4,002 2 2,153 9 3 1010 3 10 4,002 2 2,153 99 3 101012 4,002 2 2,153 4,002 2 2,153 1,849 7 How is regrouping thousands shown in the problem above? 8 Why is the 10 crossed out in the hundreds column? 9 Explain the regrouping shown in the tens column. 10 Why are 12 ones shown in the ones column? 11 Explain how to subtract two four-digit numbers if you need to regroup in all places. Try It Use what you just learned to solve these problems. Show your work on a separate sheet of paper. 12 There were 11,402 fans at the Hawks game and 9,617 fans at the Bulls game. How many more fans attended the Hawks game than the Bulls game? 13 129,027 2 98,918 5 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. 21 Part 4: Guided Practice Lesson 3 Study the model below. Then solve problems 14–16. Student Model The student regrouped 1 ten to make 10 ones. Sallie earned $4,580 last month. Her bills for that month totaled $3,178. How much money does Sallie have left after she pays her bills? Look at how you could show your work. 7 10 4,580 2 3,178 1,402 Pair/Share What is another way you could solve this problem? What operation can you use to solve this problem? Solution: $1,402 14 The population of Turtle Valley is 407,989. The population of Art Creek is 86,966. What is the total population of the two cities? Show your work. Pair/Share How did you decide which operation to use? 22 Solution: L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Part 4: Guided Practice 15 On Friday, 13,728 tickets were sold for a play. On Saturday, 15,419 tickets were sold, and 12,399 tickets were sold on Sunday. What was the total number of tickets sold for the play? Lesson 3 Does this problem use addition or subtraction? Show your work. Pair/Share Solution: 16 The Pyramid of Khafra, in Egypt, is 448 feet tall. The Eiffel Tower, in France, is 1,063 feet tall. How much taller is the Eiffel Tower than the Pyramid of Khafra? Circle the letter of the correct answer. How can you check your answer? Do you need to regroup to solve this problem? A 515 feet B 615 feet C 625 feet D 1,511 feet Cara chose D as the correct answer. How did she get that answer? L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Pair/Share How can you tell if Cara’s answer is reasonable by looking at the two given heights? 23 Part 5: Common Core Practice Lesson 3 Solve the problems. 1 Josh’s web site had 805,289 visitors. Diego’s site had 784,976 visitors. How many more visitors did Josh’s site have than Diego’s? A20,313 B21,313 C101,713 D181,713 2 Prince Edward Island in Canada is made up of three counties: Kings, Prince, and Queens. In 2011, there were 17,990 people living in Kings. There were 44,348 people living in Prince. How many people were living in Queens if the total number of people living on Prince Edward Island was 140,204? A62,338 B77,866 C122,134 D202,542 3 Tell whether each number sentence is True or False. 24 a.538 1 491 5 1,029 True False b.8,902 2 3,407 5 5,405 True False c.16,234 2 5,235 5 999 True False d.729 1 385 5 1,014 True False L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Part 5: Common Core Practice Lesson 3 4 Seventh- and eighth-grade students attend the junior high school. This year there are 122 more seventh graders than there were last year. Use this information to fill in the data that are missing from the table. 7th Graders Last Year This Year 8th Graders 1,043 Total 2,185 1,027 5 A school raised $13,809 during its fall fundraiser and $20,786 during its winter fundraiser. The goal for all fundraisers is $50,000. How much more money does the school need to raise during the spring fundraiser to reach its goal? Show your work. Answer The school needs to raise during the spring fundraiser. 6 Effie’s store has 10,908 more comic books than Brody’s store. Brody’s store has 45,607 comic books. How many comic books do Effie’s and Brody’s stores have altogether? Show your work. Answer The stores have comic books altogether. Self Check Go back and see what you can check off on the Self Check on page 1. L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. 25 Develop Skills and Strategies Lesson 3 (Student Book pages 16–25) Add and Subtract Whole Numbers Lesson Objectives The Learning Progression •Use the standard algorithm to add multi-digit whole numbers. In Grade 3, students fluently added and subtracted 2- and 3-digit numbers. In Grade 4, students are expected to be proficient with adding and subtracting numbers up to 999,999. In this lesson, students use the strategies they have gained in earlier grades to build an understanding of the standard algorithm. The use of place-value charts helps students begin to understand the process of lining up numbers by place value. This is an important concept to master, because in Grade 5 students will extend this concept to add and subtract with decimals. •Use the standard algorithm to subtract multi-digit whole numbers. Prerequisite SkilLs In order to be proficient with the concepts/skills in this lesson, students should: •Recall basic addition facts. •Recall basic subtraction facts. •Understand place value. Teacher Toolbox •Recognize addition and subtraction as inverse operations. Vocabulary There is no new vocabulary. Ready Lessons Teacher-Toolbox.com Prerequisite Skills 4.NBT.B.4 4.NBT.4 ✓ ✓ ✓ ✓ Tools for Instruction Interactive Tutorials CCSS Focus 4.NBT.B.4 Fluently add and subtract multi-digit whole numbers using the standard algorithm. ADDITIONAL STANDARDS: 4.NBT.A.2 (See page A44 for full text.) STANDARDS FOR MATHEMATICAL PRACTICE: SMP 2, 5, 7, 8 (see page A9 for full text) L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. 19 Part 1: Introduction Lesson 3 At a Glance Students read a word problem and answer a series of questions to explore a method to add a 3-digit number to a 4-digit number. Develop skills and strategies Lesson 3 Part 1: introduction ccss 4.nbt.b.4 add and subtract Whole numbers in this lesson, you will use place-value understanding and basic facts to add and subtract numbers. take a look at this problem. Step By Step Katie has 3,437 stamps in her collection and Steve has 942 stamps in his •Tell students that this page models how to add two numbers by place value. collection. How many stamps do Katie and Steve have in all? explore it •Have students read the problem at the top of the page. use the math you already know to solve the problem. What operation can you use to find the number of stamps Katie and Steve have in all? addition •Work through Explore It as a class. •Ask students to explain how they found the total number of ones. What is the sum of the digits in the ones place? 9 What is the sum of the digits in the tens place? 7 What is the sum of the digits in the hundreds place? 13 What is the sum of the digits in the thousands place? •Ask students to explain the significance of the fact that there are more than 10 hundreds. Which place value has a sum of more than 10? 3 hundreds Explain how you can find the number of stamps Katie and Steve have in all. you can think of 13 hundreds as 1 thousand 1 3 hundreds. •Ask student pairs or groups to explain their answers for the remaining questions. then you can add the thousands, hundreds, tens, and ones: 3,000 1 1,000 1 300 1 70 1 9 5 4,379. so, katie and steve have 4,379 stamps in all. SMP Tip: Students are learning how to make sense of large numbers and their meaning in contextual situations. Guide students to make connections between place value, operations with large numbers, and their relationships in problem situations. (SMP 2) 16 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Mathematical Discourse •How can place value be used to determine the sum or difference of two numbers? Students’ responses should include the concept of finding the sum of each place value and then regrouping when the sum of the digits in a place value is greater than 10. Likewise, you subtract the digits in each place value and borrow and regroup when the top digit is smaller than the bottom digit. 20 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Part 1: Introduction Lesson 3 At a Glance Students use the standard algorithm to add two numbers. They learn that you can add the ones digits, the tens digits, the hundreds digits, and the thousands digits. Once they have partial sums for each place value, the sum of the partial sums is the grand total. Step By Step •Read Find Out More as a class. •Point out that there are four partial sums because there are four digits in the greater number. •Walk through the equation and make sure students understand how each partial sum is derived. Pay special attention to the sum of the digits in the hundreds place. Hands-On Activity Use counters to understand adding numbers. Materials: beads (4 different colors) or other form of counters, one piece of paper for each student with a line drawn horizontally to divide the paper in half Part 1: introduction Find out More There are many different ways to add numbers. For example, you can use base-ten blocks, or place-value drawings. You can break numbers apart and add the parts. When you add numbers in the thousands, some methods are more convenient than others. You can stack the numbers and line up place values. Here is one way to find the sum on page 16. Add from right to left. Add the ones, add the tens, add the hundreds, and then add the thousands. 3,437 1 942 •Write an addition problem on the board. •Students should represent each number using their beads (for example, 1,423 would be 1 green, 4 yellow, 2 blue, and 3 red beads). Have students put the beads for each number above the line on their paper. 7 ones 1 2 ones 5 9 ones 3 tens 1 4 tens 5 7 tens 4 hundreds 1 9 hundreds 5 13 hundreds or 1 thousand 1 3 hundreds 3 thousands 9 70 1,300 1 3,000 4,379 Katie and Steve have 4,379 stamps in all. reflect 1 Solve the problem above by adding left to right: thousands, hundreds, tens, ones. Describe how the methods are alike and how they are different. 3,437 1 942 3,000 1,300 70 1 9 4,379 the answer is the same. the four sums are the same, but the order is reversed. L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC •Identify the place value represented by each color (for example, red: ones, blue: tens, yellow: hundreds, green: thousands). Post a visual reminder of what each color represents on the board for students. Lesson 3 Copying is not permitted. 17 Real-World Connection Have students name everyday places and situations in which large numbers are combined (added) or separated (subtracted). Examples: attendance at sporting events, number of students attending a school, amount of money earned by an adult or small business •Show students how the beads can be grouped together by color to represent addition by place value. Have students group the beads together below the line on their paper. •Explain to students that if there is more than 10 of any one color they must exchange 10 of that color for 1 bead of the next higher place value. For example, 12 blue beads would be changed to 1 red bead and 2 blue beads. •Provide students with additional problems to practice independently using the beads. L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. 21 Part 2: Modeled Instruction Lesson 3 At a Glance Part 2: Modeled instruction Students use partial sums and the standard algorithm to find the total of two given values. Lesson 3 read the problem below. then explore different ways to add four-digit numbers. At a fair, 4,657 ride tickets were sold on Saturday and 3,804 were sold on Step By Step Sunday. How many tickets were sold in all during those two days? •Read the problem at the top of the page as a class. Model it you can use place value to add. add ones to ones, tens to tens, hundreds to hundreds, thousands to thousands. •Read the first Model It. Have a volunteer explain which key words in the problem indicate that it is an addition problem. [sold in all] 4,657 1 3,804 11 50 1,400 1 7,000 •Ask students how many partial sums are shown. [4] 7 ones 1 4 ones 5 11 ones or 1 ten 1 1 one 5 tens 1 0 tens 5 5 tens 6 hundreds 1 8 hundreds 5 14 hundreds or 1 thousand 1 4 hundreds 4 thousands 1 3 thousands 5 7 thousands 8,461 •Have students identify the place values in which regrouping could occur. [ones and hundreds] Model it you can record the sums by showing regrouping above the problem. 1 •Read the second Model It. 4,657 1 3,804 •Ask students to explain why there is an extra digit above the numbers in the tens column. 4,657 1 3,804 1 61 1 •Ask a volunteer to predict where another such small digit may be placed if the addition problem continues using this algorithm. Use base-ten blocks to understand adding numbers. Materials: base-ten blocks (blocks, rods, flats, and cubes) •Present students with various 1-, 2-, 3- and 4-digit numbers and have them practice representing numbers with the base-ten blocks. Students should have a strong understanding of representing numbers before moving to addition. 1 ten 1 5 tens 1 0 tens 5 6 tens 1 4,657 1 3,804 461 1 6 hundreds 1 8 hundreds 5 14 hundreds or 1 thousand 1 4 hundreds 1 4,657 1 3,804 8,461 Hands-On Activity 7 ones 1 4 ones 5 11 ones or 1 ten 1 1 one 1 18 1 thousand 1 4 thousands 1 3 thousands 5 8 thousands L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Mathematical Discourse •Explain how to add numbers with regrouping. Students should be able to identify sums that are 10 or greater and will require regrouping. For example, the sum of 7 and 4 is 11, which is 10 1 1. The 1 more ten would need to be added to the tens column. •Present an addition problem using 3- and 4-digit numbers on the board for the class. •Students should represent each number using their base-ten blocks. •Show students how the blocks can be grouped together to represent addition. •Explain to the students how to regroup when groups of 10 or 100 can be made. •Provide students with additional problems to practice independently using the blocks. 22 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Part 2: Guided Instruction Lesson 3 At a Glance Students revisit the problem on page 18. Step By Step •Read Connect It as a class. Be sure to point out that the questions refer to the problem on page 18. Part 2: guided instruction Lesson 3 connect it now you will see how to solve the problem by showing all the steps at once. 2 Here is what the second model looks like showing all the steps at once. 1 1 4,657 1 3,804 8,461 •Have students explain their answer to problem 3. Have students use a colored pencil or some other media to connect the partial sums on page 17 to the model on page 18. The sum of the ones values is 11. Where do you see the 11 in the equation above? the 1 above the tens place and the 1 in the ones place 3 The sum of the hundreds values is 1,400. Where do you see the 1,400 in the equation above? the 1 above the thousands place and the 4 in the hundreds place 4 Why are there numbers above the tens place and above the thousands place? SMP Tip: Explain to students that there are multiple ways to solve a problem and to arrive at the correct solution. Students should begin to see patterns in adding and subtracting large numbers and become fluent in using more general methods and shortcuts to solve problems. (SMP 8) there are more than 10 ones, so you need to regroup 10 ones as 1 ten. there are more than 10 hundreds, so you need to regroup 10 hundreds as 1 thousand. 5 Explain how to add two four-digit numbers if you need to regroup tens and hundreds. Possible answer: add the ones, add the tens, and regroup 10 tens as 1 hundred. then add the hundreds, including the regrouped hundred, and regroup 10 hundreds as 1 thousand. add the thousands including the regrouped thousand. try it use what you just learned to solve this problem. show your work two ways on a separate sheet of paper. 6 A video game company sold 5,680 copies of its new game on the first day and 3,235 copies on the second day. In just two days, how many copies of the game did the company sell? 8,915 copies L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC ELL Support Students may show proficiency working with the algorithms for adding or subtracting numbers but not fully understand the vocabulary and concepts of place value. Have students talk about their mathematical thinking to ensure they fully understand both the vocabulary and concepts. Students may become confused when reading word problems and determining the correct operation. For example, the question “how many are left” could be confusing if the student interprets “left” as a directional word instead of a word signaling subtraction. L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Copying is not permitted. 19 Try It Solutions 6Solution: 8,915 copies; Students may add the numbers using partial sums or may use the standard algorithm. The sum of the digits in the tens place will have to be regrouped when using the standard algorithm. ERROR ALERT: Students who wrote 8,815 did not regroup properly or they forgot to include the extra 1 when adding the hundreds. Students who wrote 8,816 did not regroup properly. Those students regrouped the number of tens in the tens and ones places instead of in the hundreds and tens places. 23 Part 3: Modeled Instruction Lesson 3 At a Glance Part 3: Modeled instruction Students use a place-value chart to subtract one number from another. read the problem below. then explore different ways to subtract numbers. Last week, Mr. Diaz flew 4,002 miles for work. This week, he flew 2,153 miles. Step By Step How many more miles did Mr. Diaz fly last week than this week? •Read the problem at the top of the page as a class. Model it you can use place value to subtract 4,002 2 2,153. •Read Model It. Have a volunteer explain which key words in the problem indicate that it is a subtraction problem. [more miles last week than this week] You can’t subtract 3 from 2, so you need to borrow and regroup to subtract the ones digits. Write 4,002 in a place-value chart. You can’t borrow from the tens or hundreds places, so borrow from the thousands place. Keep regrouping until you can subtract. thousands hundreds tens 4 0 0 •Have students explain why they need to regroup 4 thousands as 3 thousands and 10 hundreds. Look for answers that indicate 1 hundred cannot be taken away from 0 hundreds. Materials: 1 digit number cards, wipe-off boards, and dry-erase markers 2 4 thousands 5 3 thousands 1 10 hundreds 10 2 10 hundreds 5 9 hundreds 1 10 tens 9 10 1 2 5 12 3 10 0 3 9 3 9 2 20 Use number cards to understand subtracting numbers. ones 2 10 tens 5 9 tens 1 10 ones Now you can subtract. •Have students explain why they need to regroup 10 hundreds as 9 hundreds and 10 tens. Look for answers that indicate 5 tens cannot be taken away from 0 tens. Hands-On Activity Lesson 3 thousands hundreds tens 3 9 9 2 1 5 1 8 4 ones 12 3 9 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Mathematical Discourse •How can you use estimation to check your answer to a subtraction problem? Listen for responses that use rounding each number to the nearest thousand or hundred and finding the estimated difference. •Students select 4 cards and place them in order to represent the ones, tens, hundreds, and thousands places of a number. •Students select 4 more cards to represent the digits of the second number. •Students write out the two numbers formed by the cards on their wipe-off board, putting the greater number on top and the lesser number on the bottom. •Students use place value or regrouping methods to subtract the two numbers. •This activity can be started by using only 2 number cards and working up to 4. 24 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Part 3: Guided Instruction Lesson 3 At a Glance Students revisit the problem on page 20. Step By Step •Read Connect It as a class. Be sure to point out that the questions refer to the problem on page 20. •Have students explain their answer to problem 11. Ask, Why do you need to regroup the amount in the ones column? [You cannot take 3 ones away from 2 ones.] •Ask, For every subtraction problem, will you always have to regroup in each place value? [No; only when there are more units in the place value position of the number being subtracted than there are in the number being subtracted from.] Part 3: guided instruction Lesson 3 connect it now you will solve the problem from the previous page by showing regrouping above the problem. 4,002 2 2,153 3 10 4,002 2 2,153 9 3 1010 4,002 2 2,153 99 3 101012 4,002 2 2,153 1,849 7 How is regrouping thousands shown in the problem above? 4 thousands is changed to 3 thousands and the hundreds digit is changed to 10. 8 Why is the 10 crossed out in the hundreds column? 1 hundred needs to be regrouped and added to the tens column. 9 Explain the regrouping shown in the tens column. First, 1 hundred is regrouped as 10 tens, and then 1 ten is regrouped as 10 ones. 10 Why are 12 ones shown in the ones column? a ten is regrouped as 10 ones and then added to the 2 ones. 11 Explain how to subtract two four-digit numbers if you need to regroup in all places. Possible answer: regroup 1 thousand as 10 hundreds, then 1 hundred as 10 tens, and then 1 ten as 10 ones. add the 10 ones to the top digit in the ones column, and then subtract the ones. then subtract the tens, hundreds, and thousands. try it use what you just learned to solve these problems. show your work on a separate sheet of paper. 12 There were 11,402 fans at the Hawks game and 9,617 fans at the Bulls game. How many more fans attended the Hawks game than the Bulls game? 13 129,027 2 98,918 5 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Concept Extension Help students see the connection between regrouping in an addition problem and regrouping in a subtraction problem. •Explain to students that if you do not have enough to subtract from in the ones column, then you need to borrow a group of 10 ones from the tens column. •Demonstrate with base-ten blocks how to take 10 (one rod) from the tens column and change it into 10 unit blocks to add to the ones column. Emphasize to students that even though the number looks different, the value has not changed. •Further develop the concept of regrouping with subtraction by pointing out what to do if there are no tens to borrow from. Demonstrate with baseten blocks how to borrow a group of 100 (one flat) from the hundreds column and change it into 10 rods. Explain that there are now enough tens to borrow from for the ones column. L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. 1,785 fans 30,109 Copying is not permitted. 21 Try It Solutions 12 Solution: 1,785 fans; Students need to regroup the digits in each place-value position. Before subtracting, the number representing the fans at the Hawks game will have 0 ten thousands, 10 thousands, 13 hundreds, 9 tens, and 12 ones. ERROR ALERT: Students who wrote 18,215 subtracted the lesser digit from the greater digit in each place-value position. Those students need to be reminded that they are in essence changing the location of digits from one number to another and are thereby changing the meaning of the given information. 13 Solution: 30,109; Students should regroup digits as needed. They will not need to regroup digits more than once in the tens and thousands places. 25 Part 4: Guided Practice Lesson 3 Part 4: guided Practice Lesson 3 study the model below. then solve problems 14–16. Student Model The student regrouped 1 ten to make 10 ones. Sallie earned $4,580 last month. Her bills for that month totaled $3,178. How much money does Sallie have left after she Part 4: guided Practice 15 On Friday, 13,728 tickets were sold for a play. On Saturday, 15,419 tickets were sold, and 12,399 tickets were sold on Sunday. What was the total number of tickets sold for the play? Lesson 3 Does this problem use addition or subtraction? Show your work. pays her bills? Look at how you could show your work. 7 10 4,580 2 3,178 1,402 Pair/share What is another way you could solve this problem? What operation can you use to solve this problem? Solution: $1,402 Pair/share 14 The population of Turtle Valley is 407,989. The population of Art Creek is 86,966. What is the total population of the two cities? Show your work. Solution: 41,546 tickets 16 The Pyramid of Khafra, in Egypt, is 448 feet tall. The Eiffel Tower, in France, is 1,063 feet tall. How much taller is the Eiffel Tower than the Pyramid of Khafra? Circle the letter of the correct answer. How can you check your answer? Do you need to regroup to solve this problem? a 515 feet Pair/share How did you decide which operation to use? Solution: 494,955 b 615 feet c 625 feet D 1,511 feet Cara chose D as the correct answer. How did she get that answer? she added the numbers instead of subtracting. 22 L3: Add and Subtract Whole Numbers Pair/share How can you tell if Cara’s answer is reasonable by looking at the two given heights? L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. ©Curriculum Associates, LLC Copying is not permitted. 23 At a Glance Solutions Students use place-value charts and the standard algorithm to solve problems involving addition and subtraction of whole numbers. Ex The standard algorithm is shown as one way to solve the problem. Students need to regroup the number of tens as 7 and the number of ones as 10 before subtracting in each place-value position. Step By Step 14 Solution: 494,955; Students regroup 15 ones as 1 ten and 5 ones, 15 tens as 1 hundred and 5 tens, 19 hundreds as 1 thousand and 9 hundreds, and 14 thousands as 1 ten thousand and 4 thousands. (DOK 1) •Ask students to solve the problems individually and label units in their calculations. •When students have completed each problem, have them Pair/Share to discuss their solutions with a partner or in a group. 15 Solution: 41,546 tickets; Students can add the numbers in any order. (DOK 2) 16 Solution: B; Finding the difference between two heights requires subtraction: 1,063 2 448 5 615. Explain to students why the other two answer choices are not correct: A is not correct because 10 hundreds 2 4 hundreds 5 6 hundreds, not 5 hundreds. C is not correct because the top ones digit was subtracted from the bottom ones digit, so no regrouping was done. (DOK 3) 26 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. Part 5: Common Core Practice Part 5: common core Practice Lesson 3 Solve the problems. 1 4 Lesson 3 Seventh- and eighth-grade students attend the junior high school. This year there are 122 more seventh graders than there were last year. Use this information to fill in the data that are missing from the table. 7th Graders 8th Graders Total 20,313 Last Year 1,043 1,142 2,185 B 21,313 This Year 1,165 1,027 2,192 C 101,713 D 181,713 5 Prince Edward Island in Canada is made up of three counties: Kings, Prince, and Queens. In 2011, there were 17,990 people living in Kings. There were 44,348 people living in Prince. How many people were living in Queens if the total number of people living on Prince Edward Island was 140,204? A 3 Part 5: common core Practice Josh’s web site had 805,289 visitors. Diego’s site had 784,976 visitors. How many more visitors did Josh’s site have than Diego’s? A 2 Lesson 3 A school raised $13,809 during its fall fundraiser and $20,786 during its winter fundraiser. The goal for all fundraisers is $50,000. How much more money does the school need to raise during the spring fundraiser to reach its goal? Show your work. Possible work: Money raised 1 62,338 B 77,866 C 122,134 D 202,542 1 50,000 2 34,595 15,405 Answer The school needs to raise 6 Tell whether each number sentence is True or False. 3 True a. 538 1 491 5 1,029 b. 8,902 2 3,407 5 5,405 True c. 16,234 2 5,235 5 999 True d. 729 1 385 5 1,014 True False 3 False 3 False 3 False Money left to raise 4 9 9 9 10 13,809 1 20,786 34,595 $15,405 during the spring fundraiser. Effie’s store has 10,908 more comic books than Brody’s store. Brody’s store has 45,607 comic books. How many comic books do Effie’s and Brody’s stores have altogether? Show your work. Possible work: effie’s store 1 1 45,607 1 10,908 56,515 Answer The stores have 102,122 both stores 11 1 56,515 1 45,607 102,122 comic books altogether. self check Go back and see what you can check off on the Self Check on page 1. 24 L3: Add and Subtract Whole Numbers L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. At a Glance Students use place-value concepts and regrouping to solve problems that might appear on a mathematics test. Solutions 1Solution: A; Subtract the number of visitors to Diego’s site from the number of visitors to Josh’s site. (DOK 1) 2Solution: B; Find the population of Kings and Prince. Subtract the sum from the population of Prince Edward Island. (DOK 2) 3Solution: a. True b. False c. False d. False (DOK 2) L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted. ©Curriculum Associates, LLC Copying is not permitted. 25 4Solution: See completed table above; Add last year’s 7th graders (1,043) and 122 to find this year’s 7th graders (1,165). Then add 1,165 and this year’s 8th graders (1,027) to find the total for this year (2,192). Finally, subtract last year’s 7th graders (1,043) from last year’s total (2,185) to find last year’s 8th graders (1,142). (DOK 2) 5Solution: $15,405; Add the amounts raised in the fall and winter. Subtract that sum from the goal amount, $50,000. (DOK 2) 6Solution: 102,122; Add to find the number of comic books in Effie’s store. Then add the number of comic books in Effie’s store (56,515) and the number of comic books in Brody’s store (45,607). (DOK 2) 27 Differentiated Instruction Lesson 3 Assessment and Remediation •Ask students to find the difference of 46,487 and 39,728. [6,759] •For students who are still struggling, use the chart below to guide remediation. •After providing remediation, check students’ understanding. Ask students to explain their thinking while finding the difference of 34,716 and 15,743. [18,973] •If a student is still having difficulty, use Ready Instruction, Level 3, Lesson 9. If the error is . . . Students may . . . To remediate . . . 86,215 have added. Remind students that “difference” means subtraction. 13,361 have subtracted each lesser digit from each greater digit. Remind students that if the digits in the number being subtracted are greater than the digits they are subtracting from, they need to regroup. 17,769 not have regrouped the ten thousands, thousands, or hundreds places. Remind students that they must regroup two place values each time they need to regroup a number. 16,759 not have regrouped the ten thousands. Remind students that they must regroup all of the place values, including the ten thousands place. Hands-On Activity Challenge Activity Use paper money to understand adding and subtracting whole numbers. Adding and Subtracting with Decimals Materials: paper money from a game (ones, fives, tens, twenties, fifties, and hundreds) •Present each group of students with problems where they will need to add money or make change using whole dollar amounts only. •For adding money, have the students count out each dollar amount for the two addends. Using the paper money, find the total amount in the two groups. Have students represent their total amount of money using the smallest number of bills. Connect this to regrouping using place value. Extend the concepts of adding and subtracting with regrouping and using place value to decimals. Have students solve the problem below. During the first two football games of the season, Will played 2.75 quarters in the first game and 2.25 quarters in the second game. How many quarters did he play in his first two games? [5] If Will played a total of 15.25 quarters in the season, how many quarters of playing time did he have in the remaining games? [10.25] •Have students do the same addition problem on paper to see the connection with regrouping. •Follow the same methodology for subtraction with regrouping and connect the concept to making change. 28 L3: Add and Subtract Whole Numbers ©Curriculum Associates, LLC Copying is not permitted.
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