1. SUBSTITUTION
At the end of this lesson you should :
Be able to substitute numbers for letters
Evaluate (work out) expressions

2. If a = 3, evaluate 4 + a
swap a for 3 in the formula: 7 = 3 a

3. If y = 6, find 3y
Remember 3y means 3 x y 3
(6) y
= 18

4. If b = 5 calculate: =
(5) b 19

5. If c = -3 find: =
(-3) c 9

6. If d = -2, calculate: =
(-2) d -1

7. Find the value of 2p-5 when=
(6) 7
p=-4 =
(-4) p
-13

8. Find a – 3 when 10 – 3 = 7 5 – 3 = 2 7 – 3 = 4 3 – 3 = 0 1 – 3 = -2
5 – 3 = 2
7 – 3 = 4
3 – 3 = 0
1 – 3 = -2
0 – 3 = -3
-4 – 3 = -7

9. If p = -4, evaluate: 3(-4) = -12 -4 + 5 = 1 -4 – 2 = -6 2(-4) + 1 = -7
= 4
= 14
3(-4) – 1 = -13