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Important Questions

Rational and Irrational Numbers — Important Questions

ICSE · Class 9 · Mathematics

35 important questions from Rational and Irrational Numbers for ICSE Class 9 Mathematics, with answers. Part of the ICSE Class 9 Mathematics syllabus.

35 questions30 flashcards13 formulas & key relations5 concepts

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A nested Venn diagram illustrating the relationships between natural numbers (N), integers (Z), rational numbers (Q), and real numbers (R) as subsets of each other.
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35 Questions·
multiple choicemultiple correcttext answertrue falsematchingordering

Important Questions from Rational and Irrational Numbers

1multiple correct

Which of the following numbers are rational?

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0.333..., √16, 22/7

Step 1: Check each number. 0.333... = 1/3 (recurring decimal = rational). √16 = 4 (perfect square = rational). √7 is non-terminating non-recurring (irrational). 22/7 is already in p/q form (rational). π = 3.14159... is non-terminating non-recurring (irrational).

2text answer

Calculate: 2√3 × 3√3

3true false

The sum of a rational number and an irrational number is always irrational.

Show answer

True

Step 1: Let r be rational and i be irrational. Step 2: Assume r + i = q (rational). Step 3: Then i = q - r. Since q and r are both rational, q - r is rational. Step 4: This contradicts that i is irrational. Therefore, r + i must be irrational.

4multiple correct

Which of the following are properties of irrational numbers?

Show answer

Non-terminating, non-recurring decimals, Cannot be expressed as p/q, Product with non-zero rational is irrational

Step 1: Check each property. Non-terminating, non-recurring decimals ✓. Cannot be expressed as p/q ✓. Sum of two irrationals: (2+√3) + (2-√3) = 4 (rational) ✗. Product with non-zero rational: 2×√3 = 2√3 (irrational) ✓.

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What are the important topics in Rational and Irrational Numbers for ICSE Class 9 Mathematics?
Key topics in Rational and Irrational Numbers include Number System and Basic Classification, Rational Numbers, Comparison, and Between Them, Decimal Representation of Rational Numbers, Irrational Numbers and Their Properties. Study these first, then practise questions on each for Class 9 exams.
How many important questions are there in Rational and Irrational Numbers?
Super Tutor has 35 practice questions for Rational and Irrational Numbers, including multiple choice, multiple correct, text answer, true false, matching, ordering questions. A sample with answers is on this page.

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