Key points
Algebra is a part of maths that uses letters and symbols in the place of numbers. Each letter or symbol is a variableA quantity that can take on a range of values. and can represent a range of values.
algebraic notationA series or system of written symbols used to represent numbers, amounts or elements in mathematics. is used to present information concisely.
An algebraic statement may be an expressionA mathematical sentence expressed either numerically or symbolically made up of one or more terms., an equationA mathematical statement showing that two expressions are equal. The expressions are linked with the symbol =, a formulaA fact, rule, or principle that is expressed in words or in mathematical symbols. Plural: formulae., or an identity 鈮An equation that is true no matter what values are chosen. The identity symbol 鈮 links expressions that are identities..
Algebra uses arithmetic operations (+, 鈥, 脳, 梅) to simplify expressions, solve equations and rearrange formulae.
When writing or interpreting algebraic expressions, it is important to understand that addition and multiplication are commutativeAn operation is commutative if the order does not matter. Multiplication and addition are commutative, eg 4 脳 3 = 3 脳 4 and 4 + 3 = 3 + 4 and that subtraction and division are not.
To help your understanding of algebra, it may be useful to review negative number arithmetic.
Understanding algebraic notation
Algebraic notation presents information in a concise way. For example, when variables are multiplied they are written next to each other in alphabetical order. Eg, 饾挋饾挌 represents 饾挋 脳 饾挌
An algebraic sentence is known as an expression. Within an expression, each part is known as a termAn element within an algebraic sentence. Elements (terms) are separated by + or - signs. .
A term is one element in an algebraic sentence. It may be a constantA number or quantity that does not vary. A constant speed is a steady speed. Eg, the speed of light is constant. The speed of a car is not constant, it varies., a variableAn unknown value, usually represented by a letter like 饾挋 or 饾挌, or a combination of a coefficientA number or symbol multiplied with a variable or an unknown quantity in an algebraic term. Eg, 5 is the coefficient of 5饾拸 and one or more variables.
In algebra, division is written in fractional form. The dividend is the numeratorNumber written at the top of a fraction. The numerator is the number of parts used. Eg, for 1鈦3, the numerator is 1 and the divisor is the denominatorNumber written on the bottom of a fraction. The denominator is the number of equal parts. Eg, for 1鈦3, the denominator is 3.
Examples
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Question
Write this expression using the correct algebraic notation:
饾拑 x 饾拑 x 饾拕 x 2
Repeated multiplication by the same variable is written using index notation. 饾拑 脳 饾拑 is 饾拑虏
When variables are multiplied, they are written next to each other. The 饾拑虏 and 饾拕 are written next to each other, 饾拑虏饾拕
The coefficient (2) is written at the front of the term and gives the number of this combination of variables. The 2 is written first, 2饾拑虏饾拕
Video
Watch the video to hear Kim, a textiles designer, talk about how algebra plays a part in her work.
Writing and interpreting algebraic expressions
To interpret an expressionA mathematical sentence expressed either numerically or symbolically made up of one or more terms., each variableA quantity that can take on a range of values. is defined as representing a number of items.
The correct operation must be used in an expression.
- An amount is added on to show that the result is more. Addition is used to total values.
- An amount is subtracted to show that the result is less. Subtraction is also used to find a difference.
- An amount is multiplied to show that the result is that amount times larger. Multiplication is also used for repeated addition.
- An amount in a divisor is used to show that the result is that amount times smaller. This can include finding a fractional amount. Eg, to find a half, divide by 2
Examples
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Match the statement to the correct expression
Practise using algebraic expressions by matching the correct statement to each algebraic expression.
Recognising different algebraic statements
There are four types of algebraic statements:
- An expression is a mathematical statement with no equals symbol.
- An equation links two expressions with an equals symbol.
- A formula is a statement linking two or more variables.
- An identity means that the left-hand side of the equation is identically equal to the right-hand side, for all values of the variables. The identity symbol links expressions that are identities.
Examples
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Practise algebraic notation
Quiz
Practise recognising, writing and interpreting algebraic notation with this quiz. You may need a pen and paper to help you.
Real-life maths
Knowing algebraic notation is necessary when working with certain types of computer software.
Software engineers rely on a solid understanding of algebraic notation and processing. They create codes that make computer interfaces more user-friendly, which other software developers then make use of to enhance games or Computer-Aided Design (CAD) packages.
Game - Divided Islands
Play the Divided Islands game! gamePlay the Divided Islands game!
Using your maths skills, help to build bridges and bring light back to the islands in this free game from 大象传媒 Bitesize.
More on Expressions and formulae
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