1. Put the numbers 1 to 7 in the circles. Every line must add up to 12.
Riddle
Two fathers and two sons sat down to eat eggs for breakfast. They ate exactly three eggs, each person had an egg. How come?

2. Using Formula Week 07: Use simple formulae expressed in words
Understand and use simple equations and formulae
Understand that words and symbols in expressions and formulae represent variable quantities
Make substitutions for words and symbols in given formula
Describe everyday calculations in words, numbers and equations

3. What did we do last week?

4. What is the probability of choosing a Jack from a pack of cards?
Label your probability scale with fractions, decimals and percentages.
Draw and label (using words) a probability scale.
Probability
If the probability of choosing a red counter is 0.35, what is the probability of not choosing a red counter?
What is the probability of rolling an even number on a fair, six-sided dice?
List all possible pairings of red, yellow, green, blue, purple.
What is the probability of scoring an odd number on a spinner numbered 1-9?
If your chances of winning a raffle prize are ¼, how many prizes will you win with 20 tickets?

5. What is a formula?
A formula describes a relationship. How do you calculate the area of a room? Measure the length of the room and multiply it by the width of the room Area = Length x Width A = L X W

6. Multiply hours worked and hourly rate together
If you work for 8 hours and are paid £6.50 an hour, how much will you be paid in total?
Multiply hours worked and hourly rate together
Total pay = hours worked x hourly rate
Pay = hours Worked x hourly Rate
P = W x R
Money often motivates students!!!
Take the time to explain that w would change from week to week, r would change if you got a promotion or moved jobs.
Also worth clearing up that if you know two of P, w and r, then the other one is fixed by them.
Using the formula p = wr, work out the gross pay received for completing an 8 hour shift at an hourly rate of £6.50. You must show all working out.

7. Petrol prices
How much does it cost in Pounds to buy 20 litres of petrol at 118p/litre? Write a formula to describe how you calculated your answer.
Total cost = amount in litres x cost per litre
T = A x C
Hopefully they’ll get this as it’s similar to the wages question in the previous example.
You’ll probably need to emphasise that although mathematicians are ‘lazy’ they are also really accurate so when we miss out a sign, it’s always, always, always multiply.

8. Find the perimeter p = h + j + k
A triangle has three sides with lengths h, j and k.
Write a formula to find the perimeter.
To find the perimeter, p, add up all the sides:
p = h + j + k

9. Phone bills
What is the total cost (C) of using a phone for 50 minutes at 25p per minute, plus a monthly line rental charge of £7.50.
50 x 0.25 = £12.50
£ £7.50 = £20
You’ll probably need to mention about changing the 25p to £0.25
C = 0.25m + 7.5

11. Answers
Question 3
90 minutes
130 minutes
160 minutes
4 kg (takes 110 minutes)
Question 4
£84
£156
£72
£78 68
Cost in £ = 60 + (24 x h) (d = number of hours)
Question 5
£21
£29 £4
25 minutes
Question 1
£40
£80
£100
Cost in £ = 30 + (10 x d) (d = number of days)
Question 2
£2.57
£3.90
£6.00
Cost in £ = (0.07 x n) (n = number of photos)

12. A shopkeeper uses this formula to calculate the total cost when customers pay by monthly instalments.
C = d + 24m
          C is the total cost in pounds.
          d is the deposit in pounds.
          m is the monthly instalment in pounds.
(a)     The deposit for a wardrobe is £16. The monthly payments are £10.
          What is the total cost?
Answer £………………………………….……… (2)
(b)     How many years does it take to finish paying for goods using this formula?
Answer years (1)

13. C = d + 24m C is the total cost in pounds. d is the deposit in pounds.
          m is the monthly instalment in pounds.
(c)     The total cost of a sofa is £600.
          The deposit is £120.
          Work out the value of the monthly instalment.
Answer £  (3)