In Word Equate variable names must start with a Greek character or letter and can contain any combination of the latter and/or numbers. There are a number of symbols which can also be used as part of a variable name including commas (,), full stops (.), underscores (_), superscript star (^*) and single quotes (‘). For example “β1”,”f’c”, “M^*” and “A1a” are all valid variable names whereas “1A”, “M*” and “12b” are not. The text in a variable name is case sensitive; “A” is not the same as variable “a”. Similarly, the variable “XA” is not the same as “Xa”. This is necessary as often in equations, the uppercase variable has a different meaning to the lowercase equivalent.
So far we have dealt with simple variables and quantities. Variables are numeric values. Quantities have a numeric value and unit. The numeric value of a quantity is automatically updated when the unit is changed to another unit of the same type.