Introduction to Algebra | Algebra and Graphs | IGCSE Mathematics 0580 | Unit E2.1

IGCSE Mathematics: Introduction to Algebra. What does a letter stand for in algebra, and how do you substitute numbers into an expression or a formula? A clear lesson that starts with a worked example. Every question is shown as the exam prints it, and every step of the working says what is done and why. Three questions from a practice test are worked through at the end. Free notes for this topic: https://www.learnandrevise.com IN THIS VIDEO YOU WILL BE ABLE TO Explain that a letter can stand for any number, which is called a generalised number Read algebra such as 3x, ab, x squared and x over 2 Tell an expression from a formula Substitute numbers into an expression, including a negative number, two letters and a squared letter Substitute numbers into a formula, such as the perimeter of a rectangle and the area of a triangle QUESTIONS ANSWERED What does a letter stand for in algebra? What is a generalised number? What does 3x mean, and what does ab mean? What is the difference between an expression and a formula? What does it mean to substitute? Why does a negative number go in brackets when you substitute? How do you find the value of 2x squared minus 5 when x is minus 3? Why is a negative number squared positive? How do you use the formula for the perimeter of a rectangle? How do you use the formula for the area of a triangle? EXAM TIPS SHOWN IN THE VIDEO Brackets keep a minus sign with its number. Always put a negative number in brackets before you square it. The square of a negative number is positive, so x squared is never negative. A number and its negative have the same square. A number next to a letter means multiply. CREDITS Equations: typeset with MathJax (Apache License 2.0) #IGCSE #Maths #Algebra #Substitution ``` Tags ```text IGCSE maths, introduction to algebra, algebra for beginners, letters in algebra, generalised numbers, substitution in algebra, substitute numbers into expressions, substitute into formulas, expressions and formulas, negative numbers in brackets, perimeter of a rectangle formula, area of a triangle formula, extended maths, algebra revision, maths revision