Class 9 Mathematics Chapter 3: The World of Numbers — practice questions with answers
Free practice for Class 9 Mathematics, Chapter 3: The World of Numbers. Try the solved questions below, then take a free test with instant marking and explanations.
58 questions20 easy, 26 medium, 12 hardNCERT · CBSE · State boards
Sample questions with solutions
Q1. A herder puts one pebble in a pot for each cow that leaves and removes one for each cow that returns. Which idea is this?
- One-to-one correspondence
- Place value
- Zero
- Division
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Answer: A. One-to-one correspondence
Why: Matching objects one to one was the birth of natural numbers. [p.41]
Why: Matching objects one to one was the birth of natural numbers. [p.41]
Q2. A merchant receives 15 copper ingots for every 2 bags of spices. How many ingots does he get for 12 bags?
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Answer: 90 (± 0)
Why: 12 ÷ 2 = 6 groups; 6 × 15 = 90. [p.43]
Why: 12 ÷ 2 = 6 groups; 6 × 15 = 90. [p.43]
Q3. In Brahmagupta’s language, positive numbers were ‘fortunes’ (dhana). What were negative numbers?
- Debts (ṛiṇa)
- Gifts
- Zeros
- Fractions
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Answer: A. Debts (ṛiṇa)
Why: Debts are to the left of zero. [p.45]
Why: Debts are to the left of zero. [p.45]
Q4. The temperature in Ladakh is 4 °C at noon and drops by 15 °C by midnight. What is the midnight temperature (°C)?
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Answer: -11 (± 0)
Why: 4 − 15 = −11. [p.46]
Why: 4 − 15 = −11. [p.46]
Q5. Calculate (−8) × (−7).
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Answer: 56 (± 0)
Why: Debt × debt = fortune. [p.46]
Why: Debt × debt = fortune. [p.46]
Q6. Calculate 0 − (−14).
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Answer: 14 (± 0)
Why: Subtracting a negative = adding. [p.46]
Why: Subtracting a negative = adding. [p.46]
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Frequently asked questions
How many practice questions are there for Class 9 Mathematics Chapter 3: The World of Numbers?
58 questions (20 easy, 26 medium, 12 hard). A few are solved on this page; the free test shows the answer and explanation for every question after you submit.
Is this chapter from the NCERT book?
Yes — it follows the NCERT Class 9 Mathematics syllabus, used by CBSE and many state boards.