Algebraic Strategies Year 7

Guess & Check Backtracking Balance Algebraic Strategies

5n + 8 = 33 Try n = 4 (5 x 4) + 8 = 28 = 33 Now try n = 5 (5 x 5) + 8 = 33 Guess & check - example

Guess & check – try your own

Backtracking example 1 6s + 12 = 132 What is unknown? s What is happening to s ? 6 x s What is happening to 6 x s? (6 x s)+ 12 What is the result? 132 Backtracking example 1

Backtracking example 1 6s + 12 = 132 s x6 6 x s +12 (6 x s) + 12 20 120 132 - 12 6 result We undo multiply 6 by dividing by 6 We undo + 12 by subtracting 12 Backtracking example 1

(3g – 40) 20 = 13 g x3 3 x g - 40 (3 x g) - 40 (3xg) – 40 100 300 260 13 Divide by 3 +40 X 20 result We undo divide 20 by multiplying 20 We undo multiply 3 by dividing by 3 We undo subtract 40 by adding 40 Backtracking example 2

Backtracking – try your own 4s – 9 = 51 Backtracking – try your own

125 + 7j = 209 125 + 7j – 125 = 209 – 125 7j = 84 7j 7 = 84 7 j = 12 Balance – example

45 + 12g = 189 Balance – try your own