Expressions, Equations, Formulae & Identities | Algebra | Maths | FuseSchool

Expressions, equations, formulae and identities are all slightly different types of algebraic notation. In this video we’re going to discover the differences. An expression is a collection of letters and numbers, with no equals sign. An equation is two expressions that equal each other, and so can be solved. A formula is a special type of equation. It shows the relationship between different variables, like the area of a circle and the radius. A formula needs more than 1 variable - otherwise it is just an equation. An identity is another special type of equation. They are equations that are true no matter what values are chosen. The two sides of an identity are interchangeable, so we can replace one with the other at any time. Strictly speaking, for identities we should use the three bar sign which means “equivalent to”. But it is common to just see the normal equals sign. VISIT us at, where all of our videos are carefully organised into topics and specific orders, and to see what else we have on offer. Comment, like and share with other learners. You can both ask and answer questions, and teachers will get back to you. These videos can be used in a flipped classroom model or as a revision aid. Twitter: Access a deeper Learning Experience in the FuseSchool platform and app: This Open Educational Resource is free of charge, under a Creative Commons License: Attribution-NonCommercial CC BY-NC ( View License Deed: ). You are allowed to download the video for nonprofit, educational use. If you would like to modify the video, please contact us: Click here to see more videos:

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Substitution | Algebra | Maths | FuseSchool

In algebra, we replace a letter with numbers in the process known as substitution. Given the formula A = 1/2bh, if the base is 5cm and the height is 10cm, then the area is ½ X 5 X 10 because we have replaced the b with 5 and the h with 10. You just need to be be careful with negative numbers: it is