Learn on PengiSaxon Math, Course 3Chapter 3: Number & Operations

Lesson 30: Repeating Decimals

In this Grade 8 lesson from Saxon Math, Course 3, students learn how to convert fractions and mixed numbers into repeating decimals, identifying the repetend and using bar notation to represent the repeating digits. The lesson covers the three possible outcomes when converting rational numbers to decimal form — integer, terminating decimal, or non-terminating repeating decimal — and distinguishes these from irrational numbers. Students also practice rounding repeating decimals for calculations and comparing decimals such as 0.3, 0.33, and 0.3̄ by ordering them from least to greatest.

Section 1

📘 Repeating Decimals

New Concept

Fractions can convert to decimals with endlessly repeating digits. We use a bar over this repeating part, called the repetend, to write them efficiently.

The repeating digits are called the repetend. We can indicate repeating digits with a bar over the repetend. We write 0.272727...0.272727... as 0.270.\overline{27}.

What’s next

Section 2

Repetend

Property

The repeating digits in a decimal are called the repetend. We indicate repeating digits with a bar over the repetend, such as writing 0.272727...0.272727... as 0.270.\overline{27}.

Examples

  • The fraction 16\frac{1}{6} becomes the decimal 0.1666...0.1666..., which is written as 0.16ˉ0.1\bar{6}.
  • The fraction 311\frac{3}{11} becomes the decimal 0.272727...0.272727..., which is written as 0.270.\overline{27}.
  • The mixed number 2132\frac{1}{3} is written as 2.3ˉ2.\bar{3} since 13=0.3ˉ\frac{1}{3} = 0.\bar{3}.

Explanation

Some fractions are like a broken record, creating decimals with a repeating pattern. Instead of writing forever, just draw a bar over the part that repeats—the repetend! It's the ultimate math shortcut for 'this goes on and on', keeping your work neat, tidy, and delightfully dramatic.

Section 3

Rational Numbers as Decimals

Property

Converting a rational number to a decimal has three possible outcomes: it becomes an integer, a terminating decimal, or a non-terminating decimal with repeating digits.

Examples

  • Integer: The rational number 124\frac{12}{4} simplifies to the integer 33.
  • Terminating Decimal: The rational number 34\frac{3}{4} divides to become the decimal 0.750.75.
  • Repeating Decimal: The rational number 29\frac{2}{9} divides to become the repeating decimal 0.2ˉ0.\bar{2}.

Explanation

Every fraction has a decimal alter-ego! It will either stop cleanly, be a whole number, or repeat a pattern. If a decimal goes on forever without a repeating pattern, it’s not from the rational family—it’s one of those mysterious 'irrational' numbers that doesn't play by the rules.

Section 4

Comparing Repeating Decimals

Property

To arrange repeating decimals in order, write each number out to several decimal places to reveal their true magnitude and allow for an accurate comparison.

Examples

  • To compare 0.3,0.3ˉ,0.330.3, 0.\bar{3}, 0.33, we expand them: 0.3000.300, 0.333...0.333..., and 0.3300.330. The correct order is 0.3,0.33,0.3ˉ0.3, 0.33, 0.\bar{3}.
  • To compare 0.6,0.6ˉ,0.660.6, 0.\bar{6}, 0.66, we expand them: 0.6000.600, 0.666...0.666..., and 0.6600.660. The correct order is 0.6,0.66,0.6ˉ0.6, 0.66, 0.\bar{6}.

Explanation

A repeating bar can be deceiving! To truly know which decimal is bigger, you must unmask them by writing out their digits side-by-side. Expanding them a few places reveals their actual size, so you can declare a winner without any doubt. It's like a numerical face-off where truth prevails!

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 3: Number & Operations

  1. Lesson 1

    Lesson 21: Distributive Property and Order of Operations

  2. Lesson 2

    Lesson 22: Multiplying and Dividing Fractions

  3. Lesson 3

    Lesson 23: Multiplying and Dividing Mixed Numbers

  4. Lesson 4

    Lesson 24: Adding and Subtracting Decimal Numbers

  5. Lesson 5

    Lesson 25: Multiplying and Dividing Decimal Numbers

  6. Lesson 6

    Lesson 26: Transformations

  7. Lesson 7

    Lesson 27: Laws of Exponents

  8. Lesson 8

    Lesson 28: Scientific Notation for Large Numbers

  9. Lesson 9

    Lesson 29: Ratio

  10. Lesson 10Current

    Lesson 30: Repeating Decimals

  11. Lesson 11

    Lesson 31: Investigation 3: Classifying Quadrilaterals

Lesson overview

Expand to review the lesson summary and core properties.

Expand

Section 1

📘 Repeating Decimals

New Concept

Fractions can convert to decimals with endlessly repeating digits. We use a bar over this repeating part, called the repetend, to write them efficiently.

The repeating digits are called the repetend. We can indicate repeating digits with a bar over the repetend. We write 0.272727...0.272727... as 0.270.\overline{27}.

What’s next

Section 2

Repetend

Property

The repeating digits in a decimal are called the repetend. We indicate repeating digits with a bar over the repetend, such as writing 0.272727...0.272727... as 0.270.\overline{27}.

Examples

  • The fraction 16\frac{1}{6} becomes the decimal 0.1666...0.1666..., which is written as 0.16ˉ0.1\bar{6}.
  • The fraction 311\frac{3}{11} becomes the decimal 0.272727...0.272727..., which is written as 0.270.\overline{27}.
  • The mixed number 2132\frac{1}{3} is written as 2.3ˉ2.\bar{3} since 13=0.3ˉ\frac{1}{3} = 0.\bar{3}.

Explanation

Some fractions are like a broken record, creating decimals with a repeating pattern. Instead of writing forever, just draw a bar over the part that repeats—the repetend! It's the ultimate math shortcut for 'this goes on and on', keeping your work neat, tidy, and delightfully dramatic.

Section 3

Rational Numbers as Decimals

Property

Converting a rational number to a decimal has three possible outcomes: it becomes an integer, a terminating decimal, or a non-terminating decimal with repeating digits.

Examples

  • Integer: The rational number 124\frac{12}{4} simplifies to the integer 33.
  • Terminating Decimal: The rational number 34\frac{3}{4} divides to become the decimal 0.750.75.
  • Repeating Decimal: The rational number 29\frac{2}{9} divides to become the repeating decimal 0.2ˉ0.\bar{2}.

Explanation

Every fraction has a decimal alter-ego! It will either stop cleanly, be a whole number, or repeat a pattern. If a decimal goes on forever without a repeating pattern, it’s not from the rational family—it’s one of those mysterious 'irrational' numbers that doesn't play by the rules.

Section 4

Comparing Repeating Decimals

Property

To arrange repeating decimals in order, write each number out to several decimal places to reveal their true magnitude and allow for an accurate comparison.

Examples

  • To compare 0.3,0.3ˉ,0.330.3, 0.\bar{3}, 0.33, we expand them: 0.3000.300, 0.333...0.333..., and 0.3300.330. The correct order is 0.3,0.33,0.3ˉ0.3, 0.33, 0.\bar{3}.
  • To compare 0.6,0.6ˉ,0.660.6, 0.\bar{6}, 0.66, we expand them: 0.6000.600, 0.666...0.666..., and 0.6600.660. The correct order is 0.6,0.66,0.6ˉ0.6, 0.66, 0.\bar{6}.

Explanation

A repeating bar can be deceiving! To truly know which decimal is bigger, you must unmask them by writing out their digits side-by-side. Expanding them a few places reveals their actual size, so you can declare a winner without any doubt. It's like a numerical face-off where truth prevails!

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 3: Number & Operations

  1. Lesson 1

    Lesson 21: Distributive Property and Order of Operations

  2. Lesson 2

    Lesson 22: Multiplying and Dividing Fractions

  3. Lesson 3

    Lesson 23: Multiplying and Dividing Mixed Numbers

  4. Lesson 4

    Lesson 24: Adding and Subtracting Decimal Numbers

  5. Lesson 5

    Lesson 25: Multiplying and Dividing Decimal Numbers

  6. Lesson 6

    Lesson 26: Transformations

  7. Lesson 7

    Lesson 27: Laws of Exponents

  8. Lesson 8

    Lesson 28: Scientific Notation for Large Numbers

  9. Lesson 9

    Lesson 29: Ratio

  10. Lesson 10Current

    Lesson 30: Repeating Decimals

  11. Lesson 11

    Lesson 31: Investigation 3: Classifying Quadrilaterals