What is the magnification of a 10D magnifier?

The optical power of a magnifier can be calculated using the formula:
D = Г / d, where D is the optical power of the magnifier (D = 10 diopters), Г is the magnification of the magnifying glass, d is the distance of the best vision (for a magnifying glass d = 25 cm = 0.25 m).
Let’s express and calculate the magnification of the magnifying glass:
G = D * d = 10 * 0.25 = 2.5 p.
Answer: The magnifying glass gives an increase of 2.5 times.