Question

Fill in the blanks using appropriate fractions:

$\frac{5}{21}-\_\_\_=\frac{2}{21}$

Answer 1

Step 1: Subtract $\frac{5}{21}$ from both sides of the given equation and simplify.

$\frac{5}{21}-\_\_\_-\frac{5}{21}=\frac{2}{21}-\frac{5}{21}$

$-\_\_\_=\frac{2}{21}-\frac{5}{21}$

Step 2: Subtract the numerators and write the difference over the common denominator.

$$\begin{gathered} -\_\_\_=\frac{2-5}{21} \\ -\_\_\_=-\frac{3}{21} \end{gathered}$$

Step 3: Multiply both sides of the equation by $-1$.

$\_\_\_=\frac{3}{21}$

Step 4: Divide both the numerator and denominator by the common factor $3$.

$$\begin{gathered} \_\_\_=\frac{3÷3}{21÷3} \\ \_\_\_=\frac{1}{7} \end{gathered}$$

Hence, the required number is $\frac{\mathbf{1}}{\mathbf{7}}$.