math programs

I'm developing an interest in studying mathematics, and I notice that a
lot of university math departments list their main areas in the
pure-math program as "algebra, analysis, and geometry/topology"...
where does calculus fit into this bunch? Is it not considered a "big"
area? or is it not considered an area of pure math? or is it simply
considered a part of one of the areas already mentioned, and if so
which one?

thanks

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