The 30-300mm thingy on the lens refer to the focal length. Focal length on 35mm cameras can be roughly be divided into 3 categories: wide angle, standard, telephoto.
The standard lens is normally one whose focal length is from 40 to 60mm. They are typically easier to manufacture and most manufacturers used to include a 50mm prime as part of the standard kit when buying cameras, thus the term standard lens.
The wide angle is one whose focal length is less than the standard lens. Wide angles have a wider field of view than standard lens, ie standing at the same spot, you will be able to capture more of a scene than a standard lens.
The telephoto is one whose focal length is greater than the standard lens. With a telephoto, you have a narrower field of view and objects seems 'magnified', enabling you to reach out to distant objects.
See this link for examples
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