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CBSE Class 9 Number Systems — practice questions — page 2

Explore 49 free Number Systems questions in CBSE Class 9 Mathematics. Open each question or exercise to read its content, reference answers and available explanation.

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Number Systems questions and exercises with answers

Showing questions 31–49 of 49.

Convert 0.7̄ (7 repeating: 0.7777…) to a fraction:Read the answer and worked solution →Find the distance between -3 and 5 on the number line:Read the answer and worked solution →Which of the following can be written as a rational p/q in lowest terms with q having ONLY 2 as a prime factor?Read the answer and worked solution →The product 22/7 × 7 equals:Read the answer and worked solution →Compute (-3/5) × (10/9):Read the answer and worked solution →Madhava's series for π is π = 4 − 4/3 + 4/5 − 4/7 + … . Approximating π using only the first FOUR terms gives:Read the answer and worked solution →Which expression is INCORRECT?Read the answer and worked solution →How many rational numbers are there between any two distinct rationals?Read the answer and worked solution →The set of INTEGERS is denoted by the symbol:Read the answer and worked solution →Using Brahmagupta's rules, the value of (-3) × (-4) is:Read the answer and worked solution →A rational number is any number that can be expressed as:Read the answer and worked solution →Which of the following pairs of rational numbers are EQUAL?Read the answer and worked solution →To add 2/5 + 3/10, the first step is to:Read the answer and worked solution →To divide (2/3) ÷ (3/10), the operation is equivalent to:Read the answer and worked solution →The set of rational numbers Q is CLOSED under all of the following operations EXCEPT:Read the answer and worked solution →The absolute value of -5/3 is:Read the answer and worked solution →CLASS9 · Mathematics · Real Number TypesRead the answer and worked solution →CLASS9 · Mathematics · Tap Composite NumbersRead the answer and worked solution →Match the number type to an exampleRead the answer and worked solution →

Worked practice questions

Convert 0.7̄ (7 repeating: 0.7777…) to a fraction:

  1. 7/9
  2. 7/10
  3. 7/100
  4. 7/11
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Correct answer: A. 7/9

Let x = 0.777... Then 10x = 7.777... **Subtract:** 9x = 7, so x = 7/9. (Check: 7/9 = 0.777...). **General rule:** 0.d̄ (single digit d repeating) = d/9.

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Find the distance between -3 and 5 on the number line:

  1. 2
  2. 5
  3. 8
  4. -8
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Correct answer: C. 8

Distance = |a − b|. **So |5 − (−3)| = |5 + 3| = 8. Visually: from -3 to 0 is 3 units, then 0 to 5 is 5 units, total 8.**

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Which of the following can be written as a rational p/q in lowest terms with q having ONLY 2 as a prime factor?

  1. 1/3
  2. 1/12
  3. 1/8
  4. 1/15
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Correct answer: C. 1/8

1/8 = 1/2³ — denominator has only prime 2. 12 = 2² × 3 (has 3) 15 = 3 × 5 (has 3, 5) 3 = 3 (has 3). Only 1/8 fits the criterion. *Note: 1/8 = 0.125 (terminating decimal — predictable from this property).*

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More Mathematics topics

MensurationPolynomialsAlgebraic IdentitiesLinearpolynomialsSequencesPerimeter and AreaProbabilityStatistics