NCERT Solutions for Class 9th Maths Chapter 3 .4.1 Representation of Rational Numbers on the Number Line — Think and Reflect
Book page 513 Updated on2026-09-08
Q1.
Try and represent 8/5 and – 7/4 on a number line.
Answer
Follow the chapter's rule: to mark p/q, cut the unit interval into q equal parts and count p of them from 0 — right if the number is positive, left if it is negative.
8/5 = 1 3/5, so it lies between 1 and 2
cut the interval from 1 to 2 into 5 equal parts
move 3 parts to the right of 1
−7/4 = −1 3/4, so it lies between −2 and −1
cut the interval from −1 to −2 into 4 equal parts
move 3 parts to the left of −1
−7/4 sits three quarter-steps to the left of −1; 8/5 sits three fifth-steps to the right of 1.
Why it happens: the two numbers need different rulers. Fifths and quarters do not share tick marks, so each one is located inside its own unit interval. If you wanted both on the same set of ticks you would use twentieths: 8/5 = 32/20 and −7/4 = −35/20.