A formula is a rule or equation used to calculate the value of a quantity. The plural of formula is formulae or formulas. There are all types of formulae for calculating various quantities in many areas of life. Examples
The subject of a formula is the term which is often on its own on the left hand side. e.g. For the cost of pizzas formula above the subject of the formula is C Substitution into a FormulaTo find the value of a quantity in a formula we put given values into a formula in place of the variables (written as letters). e.g. A = lw is the formula for finding the area of a rectangle. If l = 5 cm and w = 7 cm A = 5 × 7 cm^{2} A = 35 cm^{2} |