https://www.astronomy.com/observing/how-does-one-determine-magnification-i-have-an-edmund-scientific-astroscan-4-1-8-inch-aperture-f-4-2-reflecting-telescope-used-with-a-2-5x-barlow-lens-and-a-28mm-plossl-eyepiece/
Michael Bakich breaks down how to calculate the magnification for any telescope and eyepiece combination.
how doesi haveedmund scientificonedetermine