numbers this focuses on numbers and simple mathematics in python integers and decimal numbers because of the way computer chips are designedintegers and decimal numbers are represented differently on computers decimal numbers are represented by what are called floating point numbers the important thing to remember about them is you typically only get about or so digits of precision it would be nice if there were no limit to the precisionbut calculations run lot more quickly if you cut off the numbers at some point on the other handintegers in python have no restrictions they can be arbitrarily large for decimal numbersthe last digit is sometimes slightly off due to the fact that computers work in binary (base whereas our human number system is base as an examplemathematicallywe know that the decimal expansion of / is with the threes repeating forever but when we type / into the python shellwe get this is called roundoff error for most practical purposes this is not too big of dealbut it actually can cause problems for some mathematical and scientific calculations if you really need more precisionthere are ways see section math operators here is list of the common operators in python