1. 17-Aug-15Created by Mr.Lafferty Maths Dept Formulae Formulae expressed in words www.mathsrevision.com Working with Expressions Evaluating Formulae S4

2. 17-Aug-15Created by Mr.Lafferty Maths Dept Starter Questions Starter Questions www.mathsrevision.com S4

3. 17-Aug-15Created by Mr.Lafferty Maths Dept www.mathsrevision.com Learning Intention Success Criteria 2.Solving expressions showing working. 1.To explain the process of working out expressions by Formulae method. 1.Understand process of Formulae. S4 Formulae

4. 17-Aug-15Created by Mr.Lafferty Maths Dept If a = 3 and b = 9 evaluate a + b 3+9= =12 Sub in a=3 Sub in b=9 www.mathsrevision.com S4 Formulae

5. 17-Aug-15Created by Mr.Lafferty Maths Dept If a = 3 and b = 9 evaluate ab Sub in a=3 Sub in b=9 Remember ab means a x b a x b 3 x 9= =27 www.mathsrevision.com S4 Formulae

6. 17-Aug-15Created by Mr.Lafferty Maths Dept If a = 3 and b = 9 evaluate 4b Sub in b=9 Remember 4b means 4 x b 4 x b 4 x 9= =36 www.mathsrevision.com S4 Formulae

7. 17-Aug-15Created by Mr.Lafferty Maths Dept If a = 5 and b = 6 evaluate 1.a + b 2.ab 3.3a 4.b - a 5.4b 6.3ab =11 =30 =15 =1 =24 =90 www.mathsrevision.com S4 Formulae

8. 17-Aug-15Created by Mr.Lafferty Maths Dept If a = 5 and b = 3 evaluate 2a + 4b Sub in a=5 Sub in b=3 Remember 2a means 2 x a 2 x a + 4 x b 2x2x 5+ 4x4x 3 = = =10 + 12 = 22 www.mathsrevision.com S4 Formulae

9. 17-Aug-15Created by Mr.Lafferty Maths Dept If a = 5 and b = 3 evaluate a Sub in a=5 Remember a 2 means a x a a x a 5 x 5 = = =25 2 www.mathsrevision.com S4 Formulae

10. 17-Aug-15Created by Mr.Lafferty Maths Dept b Remember a means a ÷ b If a = 15 and b = 3 evaluate a Sub in a = 15 15 3 = =5 b Sub in b = 3 www.mathsrevision.com S4 Formulae

11. 17-Aug-15Created by Mr.Lafferty Maths Dept If a = 2 and b = 6 evaluate 1)4a + 3b 2)a 2 3)b 2 5)4a 2 4)5b – 3a 6) b a =26 =4 =36 =24 =16 =3 www.mathsrevision.com S4 Formulae

12. www.mathsrevision.com Now try Ex 1 Ch14 (page 162) Formulae S4

13. www.mathsrevision.com Starter Questions 5 cm 2.5 cm 3 cm 4 cm 3 cm www.mathsrevision.com S4

14. www.mathsrevision.com Learning Intention Success Criteria 1.To explain how to work with formulae expressed in words. 1.Understand formulae expressed in words. Formulae 2.Solve problems given formulae in words. S4

15. www.mathsrevision.com Sometimes formulae are expressed in words. S4 Formulae A tile fitter charges £20 per hour. How much will he charge for 8 hours of work. C =20 x h For h = 8 C = 20 x 8 =£160

16. www.mathsrevision.com S4 Formulae The cost for hiring a carpet cleaner is £30 plus £3 a day How much will it cost to hire for a week. C =30+3d For d = 7 C = 30 + 3 x 7 = £51

17. www.mathsrevision.com S4 Formulae Profit : Subtract how much you paid for goods in the first place from the amount you actually sold them for. How much profit did Daniel make if he bought a CD for £9.99 and sold it for £12 + Profit = 12 – 9.99 = £2.01

18. www.mathsrevision.com Now try Ex 2 Ch14 (page 164) Formulae S4

19. www.mathsrevision.com Starter Questions 1.Does 3 + 2 x 4 = 11 or 20 S4

20. www.mathsrevision.com Learning Intention Success Criteria 1.To explain how to evaluate formulae 1.Understand the term formulae. Formulae 2.Be able to substitute values into formulae and evaluate properly using BODMAS. S4

21. www.mathsrevision.com Formulae A formula is the process calculating a quantity based on a known relationship e.g. Length, Area, Volume etc........ It is VERY important that we remember a keypoint when working with formulae. B O D M A S Brackets Other  squares and square root etc.... Divide Multiplication Addition Subtraction S4

22. www.mathsrevision.com Formula for Parallelogram Example 1 : Find the area of parallelogram. 9cm 3cm S4

23. Formulae for the Volume of a Sphere www.mathsrevision.com S4 r D D = diameter Q.If the above sphere has radius 10cm. Calculate it’s volume.

24. Q.If the above cone has radius 15cm and height of 10 cm.Calculate it’s volume. Formulae for Volume of a Cone www.mathsrevision.com r h S4

25. www.mathsrevision.com Now try Ex 3 Ch14 (page 166) Formulae S4