The World of Numbers | Exercise 3.3

Question 1

Prove that the following rational numbers are equal:

(i) 23\frac{2}{3} and 46\frac{4}{6} (ii) 54\frac{5}{4} and 108\frac{10}{8} (iii) 35-\frac{3}{5} and 610-\frac{6}{10} (iv) 93\frac{9}{3} and 33

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Solution

We will simplify each rational number to its lowest terms.

Step 1 — Prove equality for (i)

Let's simplify the first rational number. The number is 23\frac{2}{3}. It is already in its simplest form.

23\boxed{\frac{2}{3}}

Now, let's simplify the second rational number. We find the greatest common divisor (GCD). The GCD of 4 and 6 is 2. We divide both numerator and denominator by 2.

46\frac{4}{6}

=4÷26÷2= \frac{4 \div 2}{6 \div 2}

23\boxed{\frac{2}{3}}

Both numbers simplify to 23\frac{2}{3}. Thus, they are equal.

Step 2 — Prove equality for (ii)

Let's simplify the first rational number. The number is 54\frac{5}{4}. It is already in its simplest form.

54\boxed{\frac{5}{4}}

Now, let's simplify the second rational number. We find the greatest common divisor (GCD). The GCD of 10 and 8 is 2. We divide both numerator and denominator by 2.

108\frac{10}{8}

=10÷28÷2= \frac{10 \div 2}{8 \div 2}

54\boxed{\frac{5}{4}}

Both numbers simplify to 54\frac{5}{4}. Thus, they are equal.

Step 3 — Prove equality for (iii)

Let's simplify the first rational number. The number is 35-\frac{3}{5}. It is already in its simplest form.

35\boxed{-\frac{3}{5}}

Now, let's simplify the second rational number. We find the greatest common divisor (GCD). The GCD of 6 and 10 is 2. We divide both numerator and denominator by 2.

610-\frac{6}{10}

=6÷210÷2= -\frac{6 \div 2}{10 \div 2}

35\boxed{-\frac{3}{5}}

Both numbers simplify to 35-\frac{3}{5}. Thus, they are equal.

Step 4 — Prove equality for (iv)

Let's simplify the first rational number. The number is 93\frac{9}{3}. We divide the numerator by the denominator.

93\frac{9}{3}

3\boxed{3}

Now, let's look at the second number. The number is 3. It is already in its simplest form.

3\boxed{3}

Both numbers simplify to 3. Thus, they are equal.

Answer

(i) 23\frac{2}{3} and 46\frac{4}{6} are equal because both simplify to 23\frac{2}{3}. (ii) 54\frac{5}{4} and 108\frac{10}{8} are equal because both simplify to 54\frac{5}{4}. (iii) 35-\frac{3}{5} and 610-\frac{6}{10} are equal because both simplify to 35-\frac{3}{5}. (iv) 93\frac{9}{3} and 33 are equal because both simplify to 33.

More questions in Exercise 3.3

Q1

Prove that the following rational numbers are equal:

(i) 23\frac{2}{3} and 46\frac{4}{6} (ii) 54\frac{5}{4} and 108\frac{10}{8} (iii) 35-\frac{3}{5} and 610-\frac{6}{10} (iv) 93\frac{9}{3} and 33

Q2

Find the sum:

(i) 25+310\frac{2}{5} + \frac{3}{10} (ii) 712+58\frac{7}{12} + \frac{5}{8} (iii) 47+314-\frac{4}{7} + \frac{3}{14}

Q3

Find the difference:

(i) 5614\frac{5}{6} - \frac{1}{4} (ii) 11834\frac{11}{8} - \frac{3}{4} (iii) 79(23)-\frac{7}{9} - \left(-\frac{2}{3}\right)

Q4

Find the product:

(i) 23×310\frac{2}{3} \times \frac{3}{10} (ii) 711×58\frac{7}{11} \times \frac{5}{8} (iii) 47×514-\frac{4}{7} \times \frac{5}{14}

Q5

Find the quotient:

(i) 23÷310\frac{2}{3} \div \frac{3}{10} (ii) 711÷58\frac{7}{11} \div \frac{5}{8} (iii) 47÷514-\frac{4}{7} \div \frac{5}{14}

Q6

Show that:

(12+34)×83=12×83+34×83\left(\frac{1}{2} + \frac{3}{4}\right) \times \frac{8}{3} = \frac{1}{2} \times \frac{8}{3} + \frac{3}{4} \times \frac{8}{3}

Q7

Simplify the following using the distributive property:

79(6734)\frac{7}{9}\left(\frac{6}{7} - \frac{3}{4}\right)

Q8

Find the rational number xx such that:

56(x+35)=56x+12\frac{5}{6}\left(x + \frac{3}{5}\right) = \frac{5}{6}x + \frac{1}{2}

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