GCSE Maths (Edexcel)

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Number Structure and calculation

Adding & Subtracting Surds

5:03 calculate exactly with fractions, surds and multiples of π; simplify surd expressions involving squares (e.g. √12 = √(4 × 3) = √4 × √3 = 2√3) and rationalise denominators
Spec A4 N8
Previous Adding & Subtracting Fractions Next Circumference of a Circle & Pi
  • Adding or subtracting thirds can simplify expressions
  • To simplify, the roots must be the same
  • Two rules for simplifying: B root A plus C root A equals B plus C root A, and B root A minus C root A equals B minus C root A
  • Practice example: Simplify root 75 minus root 27 to 5 root 3 minus 3 root 3
  • Multiple third manipulation rules may be required in a question
  • Final example: Simplify 3 root 7 plus the square root of 49 plus root 7 to 7 plus 4 root 7

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264

questions for Number

210

questions for Structure and calculation