Topic: Equations Objectives: To solve linear equations with the unknown on one side or two sides. (Level 5/6) Keywords: equation, unknown, operation, inverse, balance, solve Thursday, 14 November 2013

Mental Algebra Starter You have 10 seconds for each question (1 – 10)

1 3a +5a

2 3b b + 4

25y – 11y 3

17c + 2c – 5c 4

If d = 3, what is 4d? 5

If e = -3, what is 2e? 6

If t = 2, what is 4(t+1)? 7

If x = 5, what is 4(x-1)? 8

If d = 3, evaluate 5d+1 9

2y=6 What is y? 10

Answers 1) 8a6) -6 2) 5b + 67) 12 3) 14y8) 16 4) 14c9) 16 5) 1210) 3

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If I add 7 to a number I get 18. What is my number? My number is 11

Together 2 bags of sweets contain 40 sweets. How many sweets in each bag? Each bag contains 20 sweets

Ali will be 21 years old, in 8 years time. How old is Ali? Ali is 13 years old

Equations – Success if you can do these 3x = 6 x/4 = 2 x + 3 = 17 x – 4 = 13 3x + 4 = 25 4x – 3 = 17

© T Madas n + 5 = 12 n –5 7 n = 7

If I add 7 to a number I get 18. What is my number? n = 18 n –7 11 n = 11 My number is

Together 2 bags of sweets contain 40 sweets. How many sweets in each bag? 2b2b = 40 b x2x2 40 ÷2÷2 20 b = 20 Each bag contains 20 sweets

Ali will be 21 years old, in 8 years time. How old is Ali? a = 21 a – 8 13 a = 13 Ali is 13 years old + 8 Age now

How to solve the x + 3 = 10 type of equation

You get rid of the + 3 by - 3 But you must subtract 3 from both sides x + 3 =10 x + 3 – 3 = x = 7

For equations like x + 3 = 10 just subtract 3 from both sides x + 3 = 10 x = x = 7 Like this

How to solve the x – 3 = 7 type of equation

You get rid of the – 3 by + 3 But you must to add 3 to both sides x – 3 = 7 x – = x = 10

For equations like x – 3 = 7 just add 3 to both sides x – 3 = 7 x – = x =10 Like this

How to solve the 5x = 20 type of equation

5 x = 20 means 5 X x = 20 5 x = 20 5 X x = 20

5 x = 20 means 5 X x = 20 So, you get rid of the 5 X by ÷ 5 5 x = 20 5 X x ÷ 5 = 20 ÷ 5

5 x = 20 means 5 X x = 20 So, you get rid of the 5 X by ÷ 5 5 x = 20 5 X x ÷ 5 = 20 ÷ 5 x = 4

5 x = 20 means 5 X x = 20 So, you get rid of the 5 X by ÷ 5 But you must divide both sides by 5 5 x = 20 5 X x ÷ 5 = 20 ÷ 5 x = 4

For equations like 5x = 20 just divide both sides by the number that multiplies the x. 5x = 20 x = 20 ÷ 5 x = 4 Like this

How to solve the x/3 = 4 type of equation

x /3 = 4 x ÷ 3 = 4 It means x ÷ 3 = 4

x /3 = 4 x ÷ 3 = 4 x ÷ 3 X 3 = 4 X 3 Get rid of ÷ 3 by using a X 3 It means x ÷ 3 = 4

x /3 = 4 x ÷ 3 = 4 x ÷ 3 X 3 = 4 X 3 x = 12 Get rid of ÷ 3 by using a X 3 It means x ÷ 3 = 4

x /3 = 4 x ÷ 3 = 4 x ÷ 3 X 3 = 4 X 3 x = 12 Get rid of ÷ 3 by using a X 3 You must X 3 on both sides It means x ÷ 3 = 4

For equations like x/3 = 4 just multiply both sides by the number that divides the x. x/3 = 4 x = 4 X 3 x =12 Like this

Remember, always do the same thing to both sides. Felix is checking that you do this properly. x/3 = 12 x ÷ 3 X 3 = 12 X 3 x =36

If I double my house number and then subtract 4, I get 18. What is my house number? 2n2n = 18– 4 n x2x – 4 22 ÷2÷2 n = 11 I live at number 11

Cassie has 5 stamps. She bought another three books of stamps and now has 23 stamps. How many stamps in each book? 5 = b 3b + 5 = 23 b x3x3 23 –5– ÷3÷3 b = 6 Each book contains 6 stamps

Plenary: Evaluating your own progress Now go over your work, taking note of the mistakes and errors that you made. At what Level would you assess yourself ? Describe something that you have learned. Do you feel you have met the objectives of the lesson? Write one sentence to describe your progress in this lesson.

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