A number is a mathematical object used to count, measure, and label. The original examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can be represented in language with number words. The number system or the numeral system is the system of naming or representing numbers; that is, a mathematical notation for describing numbers of a given set, consistently using digits or other symbols. There are various types of number systems in maths, e.g. all integers, or rational numbers binary, decimal, etc. Number system helps in counting the numbers, to measure physical quantities, and to do calculations to solve daily life problems. Topics which are included in Number System are an international system of numeration, comparison of numbers, word problems on number operations, estimation, estimating the products, estimating the quotients and roman numerals.