As a Noun: 1. The part of mathematics that is concerned with the addition, subtraction, multiplication, and division of numbers. English = arithmetic. 2. Simple calculations in arithmetic. English = sums. 3. Particular amounts of something expressed as numbers that are written down. English = figures. 4. The job of keeping an accurate record of the money that is spent and received by a business or other organisation; or the person who does it. English = book-keeping, book-keeper, accountant. As a Verb or Adjective: 1. To work out a number or an amount by doing some arithmetic. English = do sums, sum, calculate, count. 2. To do the accounts, to do book-keeping.