How do you calculate magnification?

To calculate magnification, the correct method is to divide the size of the image by the actual size of the object being viewed. This calculation provides a ratio that indicates how much larger the image appears compared to the object’s true size. For instance, if an object is 2 mm in actual size and appears as 10 mm in the image, the magnification would be calculated as 10 mm (image size) divided by 2 mm (actual size), resulting in a magnification of 5x. This means the image is five times larger than the object.

Using other methods, such as addition or subtraction, does not yield a valid magnification factor, which is why those approaches do not apply in this context. Multiplying image size by actual size would lead to incorrect results as that does not represent the relationship of size comparison essential to magnification.