The formula to calculate the Magnifying Power is:
\[ MP = 1 + \frac{D}{F} \]
Where:
Let's say the least distance of distinct vision (D) is 250 mm and the focal length (F) is 50 mm. Using the formula:
\[ MP = 1 + \frac{250}{50} = 6 \]
We get a Magnifying Power of 6.