After answering some questions on the WyzAnt Resources Answers message board, I feel there is a need to explain all the equivalent ways we can interpret the above laundry list of notions that repeatedly come up in Elementary Mathematics... This equivalence is a key point in the COMMON CORE CURRICULUM for mathematics. Understanding equivalences and conceptual relationships in mathematics is the major goal of the common core! Let's start with percents, because these perhaps cause the most confusion...what does per-cent actually mean?? Well, 'centi' is a prefix used to represent 100...a centennial happens every 100 years...a centimeter is 1/100th of a meter. So if we talk about 50%=50per-cent, that is the equivalent of 50 per 100...a ratio of 50:100, or a fraction 50/100=1/2. It can also be thought of as 50 parts per whole 'cent'...or 50 parts per 100... Think of this as analogous... read more