The function library of MS Excel
A function is a ready-made formula; it is written as its name with arguments in brackets: =NAME(arg1, arg2). Functions sit by type in the Function Library group on the Formulas tab: Financial, Logical, Text, Date & Time, Lookup & Reference, Math & Trig and More Functions (statistical and others). Among the mathematical ones: FACT(n) – n!; EXP(x) – e to the power x; SIN, COS, TAN – for an angle in radians; GCD(a, b, …) – greatest common divisor; LCM(a, b, …) – least common multiple; SIGN(x) – –1 for a negative number, 0 for zero, 1 for a positive one; SQRT(x) – square root; SUMPRODUCT(array1, array2) – the sum of the products of matching elements; ROUND(number, digits) – rounding. The separator between arguments is a comma in English settings and a semicolon in Uzbek and Russian regional settings (which also use a decimal comma). In a Russian-language interface the names differ: for example GCD is NOD, ROUND is OKRUGL, SUMPRODUCT is SUMMPROIZV.
“The function wizard”: one student says the arguments, a second finds the function name (for example, “the greatest common divisor of 18, 24 and 42”), a third calculates the result in advance; then it is checked in Excel.