A fast algorithm for division with a remainder involves using the integer part of the division and the fractional part. For quick calculations on a computer, one can use the formula: Int(x/y) for the quotient and y*Frac(x/y) for the remainder. When using a calculator, simply perform x/y and ignore the decimals for the quotient, then multiply the decimal part by y to find the remainder. For manual calculations, traditional long division methods are recommended. This approach ensures efficient and accurate division with remainders in various contexts.