UNIT PREPARATION

Find a place to display a large monthly calendar for students to see and write on. As a daily routine, students will record their thinking on this calendar as they explore patterns in factors and multiples. See Unit 3 Lesson 5.

Display the class number line (0–130) where students can see and reach it with a pointer.

Attach a desk number line (0–100) to each student's desk to use throughout the year.

Display the Math Practices page where all students can see it.

Have the following tools readily available for the Daily Practice and Problems items in this unit:

LESSON SESSIONS DESCRIPTION SUPPLIES

LESSON 1

Time Again

 1 Students practice telling time to the nearest minute. They also solve problems involving time measurements to the nearest minute.
  • individual clocks
  • demonstration clock

LESSON 2

Field Trip

 2 A trip to the Field Museum in Chicago serves as a context for solving subtraction problems using mental math strategies. Students develop strategies for multidigit subtraction problems in which they decompose numbers and sketch number lines.  

LESSON 3

Subtracting with Base-Ten Pieces

 2 Students solve subtraction problems with base-ten pieces. The purpose is to help them develop a concrete understanding of the trading involved in subtraction in preparation for their work with a paper-and-pencil algorithm in the next lesson.
  • base-ten pieces

LESSON 4

Paper-and-Pencil Subtraction

 2–3 In this lesson, students solve subtraction problems using paper-and-pencil methods. They begin by recording their work with base-ten pieces on base-ten recording sheets. Then they use the standard paper-and-pencil subtraction algorithm, the compact method, to solve problems. They check their work with addition.
  • base-ten pieces

LESSON 5

Workshop: Subtraction

 2 This Workshop lesson allows students to choose from several problem sets to continue to develop and practice their strategies for solving multidigit subtraction problems. They build a subtraction strategy menu to compare the different strategies and begin to decide which strategies are more efficient for different types of problems.
  • base-ten pieces
  • clear plastic spinner, pencil and paper clip
  • paper
  • chart paper

LESSON 6

Leonardo the Traveler

 1 Students review addition and subtraction strategies and partitioning numbers while learning about other representations of numbers (e.g., the abacus, Roman Numerals) through the story Leonardo the Traveler. This story is based on the life and discoveries of the famous Italian mathematician, Leonardo Fibonacci.
     

LESSON 7

Addition and Subtraction: Practice and Estimation

 1 A dime store provides the setting for practicing addition and subtraction. The word problems offer opportunities to estimate, find exact answers, and check for accuracy.
  • desk number line (0–100)

LESSON 8

Class Party

 2 Students work in pairs or a small group to determine what they would serve at a class party given a list of party items and their prices, the number of students in the class, and a spending limit. Students explain their choices and show how their plans meet the given criteria.
  • calculators
  • desk number line (0–100)

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Suggested Title

  • Berggren, J.L. Episodes in the Mathematics of Medieval Islam. Springer-Verlag, New York, 2003.
  • Eves, Howard W. In Mathematical Circles: A Selection of Mathematical Stories and Anecdotes (Quadrants I, II, III and IV). Mathematical Association of America, Inc. Washington, D.C., 2003.
  • Ifrah, Georges. The Universal History of Numbers: from Prehistory to the Invention of the Computer. John Wiley & Sons, Hoboken, NJ, 1999.
  • Lumpkin, Beatrice. “African and African-American Contributions to Mathematics.” In African-American Baseline Essays. Portland Public Schools, Portland, OR, 1987.
  • Menninger, Karl. Number Words and Number Symbols: A Cultural History of Numbers. Dover Publications, New York, 2011.
  • Nelson, David, George Gheverghese Joseph, and Julian Williams. Multicultural Mathematics: Teaching Mathematics from a Global Perspective. Oxford University Press, New York, 1993.
  • Smith, David Eugene. History of Mathematics. Volume I. Dover Publications, New York, 1958.