Lesson 2

Tenths

Est. Class Sessions: 2–3

Developing the Lesson

Part 3. Tenths and Place Value

Have students model the numbers in Questions 25–26 using base-ten pieces. Students give the value of a pack if a flat is one whole. Help students see that a pack represents 10 by counting from one to ten as they stack 10 flats next to a pack.

Use the examples and the place value chart following Question 26 to discuss the function of the decimal point. Note that the digits to the left of the decimal point are whole numbers and those to the right indicate fractions of a whole.

Write 6.2 for students to see and ask:

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  • What does the number 6 to the left of the decimal point mean? (6 wholes)
  • What does the 2 to the right of the decimal point mean? (It shows us fractions of the whole. It means there are 2/10 of another whole more than just the 6 wholes.)
  • If a flat is one whole, show this number using base-ten shorthand. (See Figure 2.)

Write 31.6 in base-ten shorthand for students to see and say:

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  • The flat is one whole. Write the common fraction that describes this number. (316/10)
  • Write the decimal fraction that describes this number. (31.6)
  • Write a number sentence that describes this number. (30 + 1 + 0.6 = 31.6)

Assign Questions 27–32 to student pairs to provide practice with representing tenths with number lines (metersticks), base-ten pieces, base-ten shorthand, as a common fraction, decimal fraction, and with a number sentence.

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Use Check-In: Questions 30–32 in the Student Guide to assess students' abilities to measure length to the nearest meter and hundredth of a meter (centimeter) [E4], represent decimals using number lines [E5], use numbers to read and write decimals to the hundredths [E6], and compare and order decimals to the hundredths using models [E8].

Targeted practice for Expectations 5, 6, and 8 is in Lesson 6 Workshop: Decimal Concepts.

Assign the Exploring Tenths pages in the Student Activity Book for homework.

Student Guide: 459 460 461
Answers
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Student Activity Book:
Master:
Using base-ten shorthand to show 6.2
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