For your son’s birthday, you buy a box of 12 donuts costing £10.95.
a) How much have you effectively paid per donut by buying this box?
Donuts are sold individually at a cost of £1.35.
b) How much have you saved by buying a box of 12 compared to buying 12 individual donuts?
A firm favourite by students and staff, this fun problem is very practical too as it requires students to pick which of the non-calculator arithmetic methods to use. Especially in part 2 of the problem, students sometimes find the ‘per donut’ difference and the multiply that saving by 12, whilst other students multiply the individual price by 12 and then subtract from the box price. Very valuable discussions about ‘two ways to get the same answer’ often follow this video.
Teachers could extend the learning by considering:
- Grandma wants you to buy 3 individual extra donuts of her favourite flavour. What will be the total price for the box of 12 and 3 extra donuts?
- A new ‘party box’ of 30 donuts has just been launched at a price of £21.00 with an advertising poster saying ‘half the price of buying donuts individually’. Is this advertising statement true? Explain your answers, using Maths to justify your answer.