# Number

Of all the branches of GCSE Maths, the topics concerned with numbers are those which occur most frequently in everyday life. Simple arithmetic: addition, subtraction, multiplication and division through to fractions, percentages and ratios are used routinely by many both at home and at work.

The number system we use today originated from India, dating back at least to 595 AD. Introduction of this system to the West was largely due to translations of the work of the Arab mathematician Muhammad al-Khwarizmi - see the introduction to algebra (al-jabr). Interestingly, the earliest appearance of zero in this number system is almost 300 years later in 876 AD. The topics are listed here in approximately the order they should be studied, though the order becomes less important further down the list.

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