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Cogito

Grade 5 Math · Chapter 5 · Lesson 1

Practice Worksheet

Finding a Common Denominator

Cut both into the same size pieces.

10 problems · about 15 minutes · 5.NF.A.1

NameDate

Figure — use these to answer the problems

Make both bottom numbers the same and watch the bars line up.
1/2
1/3
011/21/3

1/2 is greater than 1/3.

First top number1
First bottom number2
Second top number1
Second bottom number3
Figure 1

Warm-Up Review

From earlier lessons. Loosen up before the new work.

2 problems

  1. From “Dividing Decimals”

    How many halves fit into 9?

    Answer

  2. From “When Multiplying Makes Things Smaller”

    What is 0.25 × 40?

    Answer

Warm Up

Straightforward practice. Get the method working first.

4 problems

  1. 2/3 written in fifteenths. What is the top number?

    Answer

  2. What method for finding a common denominator always works?

    • Multiply the two bottom numbers.
    • Add the two bottom numbers.

  3. A common denominator for halves and fifths?

    Answer

  4. A common denominator for thirds and sixths?

    Answer

Build It Up

The same ideas with more to keep track of.

2 problems

  1. 1/2 written in tenths. What is the top number?

    Answer

  2. 3/5 written in tenths. What is the top number?

    Answer

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

2 problems

  1. The Shared Unit

    2/3 written in twelfths. What is the top number?

    Answer

  2. The Other One

    3/4 written in twelfths. What is the top number?

    Answer