2. On your whiteboards…
How much would it cost to send a large letter first class that weighs 200g?

3. On your whiteboards…
How much would it cost to send a medium parcel second class that weighs 6kg?

4. On your whiteboards…
You want to send a large letter second class. You have £2. What is the maximum weight you can have?

5. How would you write down your working out?
When sending a small parcel the cost depends on the weight as shown in the table.
What is the cost for sending 6 booklets that weigh 75g each in a packet that weighs 25g?
How would you write down your working out?

7. 450

8. When x booklets that weigh 75g each were placed in a packet that weighs 25g, the weight was 1000g. So,
(weight of booklets) + (weight of packet)
equals 1000g, therefore use an equals sign, =,
to form the equation below
75x + 25 = 1000
1000

9. When x booklets that weigh 75g each were placed in a packet that weighs 25g, the weight was lighter than 1000g. So,
(weight of booklets) + (weight of packet)
is less than 1000g, therefore use the inequality sign, <.
It can be represented as
75x + 25 < 1000
1000

10. 75x + 25 < 1000 This is an inequality 75x + 25 = 1000
How many books can I send without paying the higher price?
75x + 25 = 1000
This is an equation
Once I send this many books
I must start paying the higher price

11. 75x + 25 < 1000 This is an inequality
There are many answers to this.
How can you generalise the answer?

12. 75x + 25 = 1000 This is an equation There is only one answer where
the total weight will be 1000g

13. On your whiteboards… What could my number be?
I subtract five from my number and my answer
is less than four.

14. I subtract five from my number and my answer
Can you write an inequality to represent this? Look at the sentence in two parts.
I subtract five from my number and my answer
is less than four.

15. I subtract five from my number and my answer
Can you write an inequality to represent this? Look at the sentence in two parts.
I subtract five from my number and my answer
is less than four.
x – 5 < 4? x – 5 > 4?

16. Understanding Algebra Statements
2x > 7
What does this mean? What values of x make it true?

17. Understanding Algebra Statements
What does this mean? What values of x make it true?

18. Understanding Algebra Statements
What does this mean? What values of x make it true?