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| source: ncert_exercises |
| topic: numbers |
| class_level: class_9 |
| chapter: ch1 |
| exercise: ex1.1 |
| difficulty: beginner |
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| Class 9 | Ch1: Number Systems | Exercise 1.1 |
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| Q1. Is zero a rational number? Can you write it in the form p/q, where p and q are integers and q ≠ 0? |
| Answer: Yes. Zero is a rational number. 0 = 0/1 = 0/2 = 0/(-3). Here p=0, q≠0, both integers. ✅ Zero IS a rational number. |
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| Q2. Find six rational numbers between 3 and 4. |
| Answer: Write 3 = 21/7 and 4 = 28/7. Six rationals: 22/7, 23/7, 24/7, 25/7, 26/7, 27/7. ✅ Many answers possible. |
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| Q3. Find five rational numbers between 3/5 and 4/5. |
| Answer: Write 3/5 = 18/30 and 4/5 = 24/30. Five rationals: 19/30, 20/30, 21/30, 22/30, 23/30. ✅ |
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| Q4. State whether true or false. Give reasons. |
| (i) Every natural number is a whole number. |
| (ii) Every integer is a whole number. |
| (iii) Every rational number is a whole number. |
| Answer: (i) TRUE — Natural={1,2,3...} ⊂ Whole={0,1,2,3...}. (ii) FALSE — Negative integers like -1,-2 are NOT whole numbers. (iii) FALSE — Fractions like 1/2, 3/4 are rational but not whole. ✅ (i)True (ii)False (iii)False. |
