LEARN NC

K–12 teaching and learning · from the UNC School of Education

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Learning outcomes

Students will:

  • review adding and simplifying fractions
  • recall the terms proper and improper
  • visualize fractions in a non-numerical way
  • create fraction equations using addition
  • solve equations in simplest form

Teacher planning

Time required for lesson

2-3 Days

Materials/resources

  • mathematics book (open to lesson on adding fractions)
  • 3×5 note card
  • small paper bag or Ziploc bag filled with dominoes
  • dominoes numbering up to 15 dots (or more)
  • lined paper (clear, white paper is optional)
  • pencil

Technology resources

Overhead projector with blank transparencies

Pre-activities

  • Students should have experienced a lesson on simplifying and adding fractions.
  • Students should have had assignments connected with these two lessons.
  • Write down a fraction problem on the overhead (i.e. 3/4+5/6=?).
  • Have students help you through each step of the process to solve the equation.
  • Students will write out each step to solve a fraction addition problem on their 3×5-note card.

Activities

  1. Take out a small bag full of dominoes.
  2. Pull two dominoes out of the bag and show the class how the dominoes look like a fraction.
  3. Review the terms improper and proper with the class.
  4. Tell students they will be working with the addition of proper fractions.
  5. Draw a pictorial of the two dominoes on the overhead and then write the numeral of the top and the bottom of the fraction right next to it.
  6. Turn those two dominoes into an addition problem by adding a plus sign and an equal sign (or bar).
  7. Have the students help you solve the problem (they may use their note card as a “cheat sheet”).
  8. When the solution is discovered, ask the students if it is “reduced”, in “lowest terms”, or “simplified”.
  9. Then, show the students how to simplify using the dots on the dominoes (see below).
  10. Have students practice with a partner setting up several different addition equations with the dominoes and solving the equation in lowest terms.

To simplify:

  • Tell the students they must always start with the top of the fraction (the numerator).
  • Ask the students how many sets divide equally into the top (i.e. if there are 2 dots, then 2 goes into itself evenly; if the number is three, then three goes into itself evenly; if there are four dots, then two sets of two dots go into four evenly and one set of four dots can also go into it evenly, and so on).
  • Once the students understand this concept, proceed to ask the students how many of those sets in the numerator can be taken away from (divided into) the bottom number of dots (the denominator).
  • If the fraction is 4/6, the students should see that the one set of four dots from the numerator cannot be taken from the denominator evenly, however, the two sets of two from the top can go evenly into the bottom three times (there are three sets of two in the denominator); since this is the case, then the fraction of 4/6 can be reduced to 2/3 because 2 sets of dots from the numerator can be evenly divided 3 times into the denominator.
  • Show the students how to redraw the new reduced fraction of dots in order to see if any more sets can be divided equally into one another (this step is important with larger fractions).
  • If the new domino fraction can be reduced more, then it must not yet be in simplest form.
  • students should know that simplest form means that you can no longer divide the numerator into the denominator evenly

Assessment

  1. Give each student a bag of dominoes.
  2. Students will create ten or so of their own fraction addition equations by pulling out two dominoes, drawing a pictorial, writing out the numbers alongside the pictorial, and solving the equations in lowest terms.

Supplemental information

Follow-up:

In the assessment, have students solve their created equations on a separate piece of paper. This will be the “answer key”. Then the next day, have the students exchange equations to solve one another’s problems. Once they’ve done this, have the students hand the paper back to its owner to check the work with their “answer key”.

Related websites

N/A

Comments

Extensions:

  • Using dominoes to set-up equations is a great activity for mixed numbers (improper fractions), as well as subtraction (make sure the larger fraction is first in the equation to avoid negative numbers), multiplication and division, and even for setting up algebraic equations.

Adaptations:

  • For those students who struggle with fractions, have a prepared bag of dominoes with the smaller numbers and assign fewer problems for them to create and solve.
  • For those students who excel in this have them make algebraic equations solving for n (i.e.: 3/4 + n= 5/8)
  • For those students who excel, you could also have them make up story problems with the dominoes or have them jump ahead to adding mixed numbers, or improper fractions.

North Carolina Curriculum Alignment

Mathematics (2004)

Grade 5

  • Goal 1: Number and Operations - The learner will understand and compute with non-negative rational numbers.
    • Objective 1.02: Develop fluency in adding and subtracting non-negative rational numbers (halves, fourths, eighths; thirds, sixths, twelfths; fifths, tenths, hundredths, thousandths; mixed numbers).
      • Develop and analyze strategies for adding and subtracting numbers.
      • Estimate sums and differences.
      • Judge the reasonableness of solutions.
    • Objective 1.03: Develop flexibility in solving problems by selecting strategies and using mental computation, estimation, calculators or computers, and paper and pencil.

Grade 6

  • Goal 1: Number and Operations - The learner will understand and compute with rational numbers.
    • Objective 1.03: Compare and order rational numbers.
    • Objective 1.04: Develop fluency in addition, subtraction, multiplication, and division of non-negative rational numbers.
      • Analyze computational strategies.
      • Describe the effect of operations on size.
      • Estimate the results of computations.
      • Judge the reasonableness of solutions.