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

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

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

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?

 

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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

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

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

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

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

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

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.

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?

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

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

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