Formulae www mathsrevision com S 4 Working with

Formulae www. mathsrevision. com S 4 Working with Expressions Formulae expressed in words Evaluating Formulae 06 -Sep-21 Created by Mr. Lafferty Maths Dept

Starter Questions www. mathsrevision. com S 4 06 -Sep-21 Created by Mr. Lafferty Maths Dept

Formulae www. mathsrevision. com S 4 Learning Intention Success Criteria 1. To explain the process of working out expressions by Formulae method. 1. Understand process of Formulae. 2. Solving expressions showing working. 06 -Sep-21 Created by Mr. Lafferty Maths Dept

Formulae www. mathsrevision. com S 4 If a = 3 and b = 9 evaluate a+b = 3+ 9 Sub in a=3 Sub in b=9 = 12 06 -Sep-21 Created by Mr. Lafferty Maths Dept

Formulae www. mathsrevision. com S 4 If a = 3 and b = 9 evaluate ab axb = 3 06 -Sep-21 x = 27 9 Remember ab means a x b Sub in a=3 Sub in b=9 Created by Mr. Lafferty Maths Dept

Formulae www. mathsrevision. com S 4 If a = 3 and b = 9 evaluate 4 b 4 xb = 4 x 9 Remember 4 b means 4 x b Sub in b=9 = 36 06 -Sep-21 Created by Mr. Lafferty Maths Dept

Formulae www. mathsrevision. com S 4 If a = 5 and b = 6 evaluate 1. a + b =11 4. b - a =1 2. ab =30 5. 4 b =24 3. 3 a =15 6. 3 ab =90 06 -Sep-21 Created by Mr. Lafferty Maths Dept

Formulae S 4 www. mathsrevision. com If a = 5 and b = 3 evaluate 2 a + 4 b = 2 xa + 4 xb = 2 x 5 + 4 x 3 = 10 = 22 06 -Sep-21 Remember 2 a means 2 x a Sub in a=5 Sub in b=3 + 12 Created by Mr. Lafferty Maths Dept

Formulae www. mathsrevision. com S 4 If a = 5 and b = 3 evaluate a 2 = a x = 5 x = 25 06 -Sep-21 a 5 Remember a 2 means a x a Sub in a=5 Created by Mr. Lafferty Maths Dept

Formulae www. mathsrevision. com S 4 If a = 15 and b = 3 evaluate a 15 = b 3 = 5 06 -Sep-21 Sub in a = 15 Sub in b = 3 Created by Mr. Lafferty Maths Dept

Formulae www. mathsrevision. com S 4 If a = 2 and b = 6 evaluate 1) 4 a + 3 b =26 4) 5 b – 3 a =24 2) a 2 =4 5) 4 a 2 =16 3) b 2 =36 6) b =3 a 06 -Sep-21 Created by Mr. Lafferty Maths Dept

Formulae www. mathsrevision. com S 4 Now try Ex 1 Ch 14 (page 162)

Starter Questions www. mathsrevision. com S 4 5 cm 2. 5 cm 3 cm 4 cm

Formulae www. mathsrevision. com S 4 Learning Intention 1. To explain how to work with formulae expressed in words. www. mathsrevision. com Success Criteria 1. Understand formulae expressed in words. 2. Solve problems given formulae in words.

Formulae www. mathsrevision. com S 4 Sometimes formulae are expressed in words. A tile fitter charges £ 20 per hour. How much will he charge for 8 hours of work. C = 20 xh For h = 8 C = 20 x 8 = £ 160

Formulae www. mathsrevision. com S 4 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 + 3 d For d = 7 C = 30 + 3 x 7 = £ 51

Formulae S 4 www. mathsrevision. com 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

Formulae www. mathsrevision. com S 4 Now try Ex 2 Ch 14 (page 164)

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

Formulae www. mathsrevision. com S 4 Learning Intention 1. To explain how to evaluate formulae Success Criteria 1. Understand the term formulae. 2. Be able to substitute values into formulae and evaluate properly using BODMAS. www. mathsrevision. com

Formulae www. mathsrevision. com S 4 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

Formula for Parallelogram www. mathsrevision. com S 4 Example 1 : Find the area of parallelogram. 3 cm 9 cm

Formulae for the Volume of a Sphere www. mathsrevision. com S 4 r D = diameter D Q. If the above sphere has radius 10 cm. Calculate it’s volume.

Formulae for Volume of a Cone www. mathsrevision. com S 4 h r Q. If the above cone has radius 15 cm and height of 10 cm. Calculate it’s volume.

Formulae www. mathsrevision. com S 4 Now try Ex 3 Ch 14 (page 166)