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In algebra, letters are used to stand for numbers.

The letters are often called variables.

It is necessary to be able to add, subtract, multiply and divide algebraic terms.

An algebraic term can be made up of coefficient, variables and exponents.
Like terms have the same variables and exponents.	e.g. { 2a, 4a, -6a } are like terms. a is common to all.   { x, 3a2, 6 } are unlike terms.  There is no common term.
An algebraic expression is a group of terms.	e.g. 4x + 3y is an expression.

 

Addition and Subtraction

An expression involving addition and subtraction can be simplified only if it contains like terms.

The like terms are collected together and then added or subtracted.

Multiplying

3xy means "3 multiplied by x multiplied by y ".

In terms of this type the number comes first and the variables are usually placed in alphabetical order.

e.g. 3q × 4p = 12pq

Note that numbers are multiplied first and letters (variables) are placed in alphabetical order.

Words into Symbols

Many maths problems are written in words and these words often have to be changed into algebraic expressions.