The World of Numbers | Exercise 3.4

Question 1

Represent the rational numbers 23\frac{2}{3}, 54-\frac{5}{4} and 1121\frac{1}{2} on a single number line.

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Solution

Let's find the position of each number on the number line.

Step 1 — Understand the values

We have three rational numbers. Let's convert them to decimals. This helps us find their positions.

For 23\frac{2}{3}: 23\frac{2}{3} =0.666...= 0.666...

0.67\boxed{\approx 0.67}

For 54-\frac{5}{4}: 54-\frac{5}{4} =1.25= -1.25

1.25\boxed{-1.25}

For 1121\frac{1}{2}: 1121\frac{1}{2} =32= \frac{3}{2} =1.5= 1.5

1.5\boxed{1.5}

Now we know their approximate values. We can see their order clearly. The smallest is -1.25. The next is 0.67. The largest is 1.5.

Step 2 — Draw the number line

We will draw a number line. We mark the integers first. Then we place our numbers. 54-\frac{5}{4} is between 2-2 and 1-1. It is one-quarter past 1-1 towards 2-2. 23\frac{2}{3} is between 00 and 11. It is two-thirds of the way from 00 to 11. 1121\frac{1}{2} is between 11 and 22. It is exactly halfway between 11 and 22.

Diagram 1

Answer

(i) 54-\frac{5}{4} is located between 2-2 and 1-1. It is one-quarter of the way from 1-1 to 2-2. (ii) 23\frac{2}{3} is located between 00 and 11. It is two-thirds of the way from 00 to 11. (iii) 1121\frac{1}{2} is located between 11 and 22. It is exactly halfway between 11 and 22.

More questions in Exercise 3.4

Q1

Represent the rational numbers 23\frac{2}{3}, 54-\frac{5}{4} and 1121\frac{1}{2} on a single number line.

Q2

Find three distinct rational numbers that lie strictly between 12-\frac{1}{2} and 14\frac{1}{4}.

Q3

Simplify the expression: (14)+(512)\left(-\frac{1}{4}\right) + \left(\frac{5}{12}\right).

Q4

A tailor has 153415\frac{3}{4} metres of fine silk. If making one kurta requires 2142\frac{1}{4} metres of silk, exactly how many kurtas can he make?

Q5

Find three rational numbers between 3.1415 and 3.1416.

Q6

Can you think of other way(s) to find a rational number between any two rational numbers?

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