source: ncert_exercises
topic: numbers
class_level: class_9
chapter: ch1
exercise: ex1.1
difficulty: beginner
Class 9 | Ch1: Number Systems | Exercise 1.1
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.
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.
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. ✅
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.