Dewey Decimal System

Dewey system is a hierarchical structure that goes from broad to specific. The first ten

categories in the hundreds is broken down to another ten subcategory in the tens place and

other ten categories in the ones place. With each subcategory, the subject narrows and

becomes more specific. By adding decimals the specialized topics are furthered narrowed.

500 Natural sciences & math

520 Astronomy & allied sciences

523 Specific celestial bodies

523.7 Sun

523.71 Constants and dimensions