1. Produced by MEI on behalf of OCR © OCR 2013 Introduction to Quantitative Methods Changing the subject of the formula © OCR 2014

2. Produced by MEI on behalf of OCR © OCR 2013 What is a formula? A formula is a relationship between different variables. Variables are represented by symbols like x or A that stands for numbers which can take different numbers A = b × h is a formula for…? © OCR 2014

3. Produced by MEI on behalf of OCR © OCR 2013 What is a formula? A = b × h This is the formula for finding the area of a rectangle. b and h are different for each rectangle © OCR 2014 b h

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5. Produced by MEI on behalf of OCR © OCR 2013 Formula © OCR 2014

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8. Produced by MEI on behalf of OCR © OCR 2013 You could write: 77 = C + 32 And solve the equation © OCR 2014

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11. Produced by MEI on behalf of OCR © OCR 2013 There are different methods to rearrange equations just like there are to solve equations. One way is to use method of balancing, remembering that any variables you have represent numbers. © OCR 2014

12. Produced by MEI on behalf of OCR © OCR 2013 Remember the = sign means the 2 sides are equal and anything you do to one side you must do to the other. Our equation is F = C + 32 This is the same as C + 32 = F © OCR 2014

13. Produced by MEI on behalf of OCR © OCR 2013 C + 32 = F -32 from both sides -32 -32 C = F - 32 ×5 on both sides ×5 ×5 9C = 5(F – 32) ÷9 on both sides ÷9 ÷9 C = © OCR 2014

14. Produced by MEI on behalf of OCR © OCR 2013 Can you set up a formula in Excel to change from degrees Celsius to degrees Fahrenheit? © OCR 2014