What is the name of the other main library classification system besides the dewey decimal system ?

Online Public Access catalog.

Explanation:

Library classification system help libraries to manage and store thousands of book and materials, it is the system which is developed to keep the library resources arranged in systematical order.

Library manages thousands of material of different subjects that need to settle in a manner that allows the easiest possible access to the end-user and he does not need to face any problem.

the entire expression should be subtracted from 30. to subtract the quantity, distribute the negative sign, which changes the signs on the terms. so, the –2 changes to positive and gets added to 30 instead of subtracted from it.

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