Indices with letters
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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
- The same laws, new letters
- Multiply and divide
Read the transcript of the teaching part
Last time
Before we start: last time, in Algebraic fractions, you learned these points. Here they are again on one card. Keep them in mind, because today builds on them.
The same laws, new letters
You already know the laws of indices with numbers. Now we meet them with letters, and with coefficients in front. The laws are exactly the same, and Cambridge loves to mix them. Today you handle numbers and letters separately, negative and fractional indices, and equations for an unknown index.
Multiply and divide
When you multiply terms, multiply the numbers, and add the indices of the same letter. When you divide, divide the numbers, and subtract the indices. With two letters, deal with each letter on its own. Twelve a to the five b squared, over four a squared b: three a cubed b. A letter on its own has an index of one. That is why b squared over b leaves just b.
How often it comes up
How often Cambridge has asked each part, counted by ExamYard from every past paper in its question bank: Indices with letters.
The whole chapter: Algebraic Fractions and Indices.
Chapter 9: Algebraic fractions and indices
- Indices with letters 5 min
- Algebraic fractions 6 min
Also for IGCSE Maths 0580
Which topics come up most in IGCSE Maths 0580 past papers, counted from every paper since 2004.