2 Objective Writing Numbers in Different Forms In order for students to work flexibly with numbers, they need to understand different representations of numbers, including standard form, expanded form, and word form. Understanding multiple representations of numbers sets the stage for multiplication and division of numbers as well as understanding and comparing fractions and decimals. Common Core State Standards 4.NBT.2 Talk About It Discuss the Try It! activity. Ask: How did you show 1,342 using Base Ten Blocks? Have students describe the blocks they used. Ask: How did you write 1,342 in standard notation? How did you write it in expanded notation? Have students compare their Number Forms Recording Sheet (BLM 4). Ask: How did you know how to separate the different parts of 1,342 when you wrote it in expanded form? Discuss with students how they separated the number into thousands, hundreds, tens, and ones. Solve It With students, reread the problem. Have students explain in writing the four ways that Mr. Mancetti s students could represent the number 1,342. Say: The next day, a group had to represent the number 2,511 four ways. Have students complete a new copy of the Number Forms Recording Sheet for 2,511. More Ideas For other ways to teach about modeling and writing numbers Establish a learning center with Base Ten Blocks. Have students take turns working at the center in pairs to play a game with blocks. One student will say a four-digit number. Then the other student builds the number with blocks. Use Cuisenaire Rods to model different numbers, and have students write the numbers in the three different forms. Formative Assessment Have students try the following problem. Which shows the word form of 5,892? A. Five thousand, eight hundred ninety B. Five thousand, eight hundred two 42 C. Five thousand, eight hundred ninety-two D. Five hundred, nine hundred eighty-two
Try It! 30 minutes Groups of 6 Here is a problem about modeling, reading, and writing one- through four-digit numbers in various forms. Mr. Mancetti s class is putting on math skits to represent a number every day. Each group of students has to represent a number in at least four different ways. Today it is time for a group to represent the number 1,342. How could the group represent the number in four ways? Introduce the problem. Then have students do the activity to solve the problem. Distribute Base Ten Blocks, a Number Forms Recording Sheet (BLM 4), paper, and pencils to students. Introduce and define the terms standard notation, expanded notation, and word form, and give students examples of the three number forms for one-, two-, three-, and fourdigit numbers. Materials Base Ten Blocks (1 cube, 10 flats, 10 rods, and 10 units per group) Number Forms Recording Sheet (BLM 4; 1 per student) paper (1 sheet per student) pencils (1 per student) 1. Ask groups to use blocks to show 1,342. Then have students draw the blocks used to model the number and write the number in standard form on their recording sheets. 2. Review expanded notation with students. Then ask students to write 1,342 on their recording sheets in expanded notation. Tell students that they can look at their blocks to help them. Watch for students who insert and into their word form for a whole number, such as one thousand, three hundred, and forty-two. Remind students that and is used for a portion (decimal) of a number. 3. Remind students that they also can write out numbers by using words. Ask groups to write 1,342 in word form on their recording sheets. 43
Lesson 2 Name Answer Key Use Base Ten Blocks to build each number. Write the number in expanded form and standard form. (Check students work.) 1. 2. 1,000 200 30 5 1,000 0 70 8 1,235 1,078 Build the number using Base Ten Blocks. Then sketch the model for the number. Write the number in standard form. 3. six thousand, three hundred twenty-one (Check students models.) 6,321 Write each number in the forms named. 3,000 4. 3,805 expanded form + + + word form 9,000 5. 9,268 expanded form + + + word form 800 three thousand, eight hundred five 200 0 60 nine thousand, two hundred sixty-eight 5 8 6. one thousand, seven hundred fifty-three 1,000 expanded form + + + 700 50 3 1,753 standard form 44 Download student pages at hand2mind.com/hosstudent.
Answer Name Key Challenge! Explain why you write a 0 in a place value while changing a number given as words into a number written in standard form. Draw a model to help. Challenge: (Sample) When the word form of a number does not include a word for each place, one of the place values will have a 0 in it. An example: if the number is greater than one thousand and the word hundred is missing, then there is a 0 in the hundreds place when the number is written in standard form. Download student pages at hand2mind.com/hosstudent. 45
Lesson 2 Name Use Base Ten Blocks to build each number. Write the number in expanded form and standard form. 1. 2. Build the number using Base Ten Blocks. Then sketch the model for the number. Write the number in standard form. 3. six thousand, three hundred twenty-one Write each number in the forms named. 4. 3,805 expanded form + + + word form 5. 9,268 expanded form + + + word form 6. one thousand, seven hundred fifty-three expanded form + + + 44 standard form www.hand2mind.com
Name Challenge! Explain why you write a 0 in a place value while changing a number given as words into a number written in standard form. Draw a model to help. www.hand2mind.com 45
Name BLM 4 Drawing Standard Form Expanded Form Word Form Number Forms Recording Sheet BLM 4 Number Forms Recording Sheet 151