Number Systems • Topic 2 of 6

Rational Numbers as Recurring/Terminating Decimals

What are Terminating and Recurring Decimals?

When we convert a rational number (p/q) to decimal form by dividing p by q, we get either:

Terminating Decimals: The division ends after a finite number of steps.

  • Example: 1/2 = 0.5, 3/4 = 0.75, 7/8 = 0.875
  • Occurs when denominator (in simplest form) has only prime factors 2 and 5

Recurring (Repeating) Decimals: The division never ends; a digit or block of digits repeats forever.

  • Example: 1/3 = 0.333..., 2/7 = 0.285714285714...
  • Represented with a bar: 0.3̅, 0.285714̅

Why Do Recurring Decimals Occur?

When denominator has prime factors other than 2 and 5 (like 3, 7, 11, etc.), the decimal repeats.

Rational Numbers & Decimal ExpansionsTerminating DecimalsNon-Terminating Repeating1/2= 0.53/4= 0.757/8= 0.8751/5= 0.21/3= 0.333...2/7= 0.285714...5/6= 0.8333...1/11= 0.0909...Rule: p/q terminates ⟺ q has only 2s and 5s as prime factorsOtherwise it repeats. Both types are RATIONAL.
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Worked Example

Solve a standard problem on Rational Numbers as Recurring/Terminating Decimals.

Solution

Apply the formula/method shown in the concept section above.

Key Points

  • Understand the definition and properties of Rational Numbers as Recurring/Terminating Decimals.
  • Study the worked examples and practice similar problems.
  • Always verify your answer using the original conditions.
Tap an option to check your answer0 / 4
Q1.A rational number has a decimal expansion that is terminating or:
Explanation: Terminating or recurring.
Q2.$\tfrac13=0.333\ldots$ is:
Explanation: A repeating decimal.
Q3.$\tfrac{p}{q}$ (lowest terms) terminates iff $q$ has only the prime factors:
Explanation: Only $2$ and $5$.
Q4.$0.75$ as a fraction is:
Explanation: $0.75=\tfrac34$.