Simplifying, substituting and forming expressions
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The teaching part (1 min) is free to watch. A free account opens the whole lecture: 7 practice questions, 2 real past-paper questions with the answers explained, the mistakes that lose marks, the full-marks tip, a one-card summary and a quick quiz.
What this lecture covers
- Algebra is a shorthand
- Algebra words
- Collecting like terms
Read the transcript of the teaching part
Last time
Before we start: last time, in Expanding brackets and factorising, you learned these points. Here they are again on one card. Keep them in mind, because today builds on them.
Algebra is a shorthand
Three adults and four children go to the cinema. If an adult ticket costs a dollars and a child ticket costs c dollars, the total is three a plus four c. Algebra turns a sentence into one short line. Today you simplify expressions, substitute numbers into them, and write expressions from words.
Algebra words
A term is a single part of an expression, like three a, or five x squared. Terms are separated by plus and minus signs. A coefficient is the number in front of a letter. In seven b, the coefficient is seven. Like terms have exactly the same letters and powers. Three x and five x are like terms. But three x and three x squared are not.
Collecting like terms
To simplify, collect like terms, keeping the sign in front of each one. Five a plus three b, minus two a, plus four b. The a terms: five a minus two a is three a. The b terms: three b plus four b is seven b. So the answer is three a plus seven b. You cannot combine a and b.
How often it comes up
How often Cambridge has asked each part, counted by ExamYard from every past paper in its question bank: Simplifying expressions · Substitution and forming expressions.
The whole chapter: Algebraic Manipulation.
Chapter 8: Algebra
- Simplifying, substituting and forming expressions 5 min
- Expanding brackets and factorising 6 min
Also for IGCSE Maths 0580
Which topics come up most in IGCSE Maths 0580 past papers, counted from every paper since 2004.