301. How much is my sandwich?

A visual discussion starter for you:

These three pots of sandwich filling cost £1 each. The flavours are egg mayo, chicken & bacon and cheese & onion.
How much would the 182g chicken filling cost if it weighed the same as the others?
The large pots contain 5 servings and the small pot contains 3 servings – are they the same size serving?

If you zoom in on the picture you could generate your own questions based on the nutritional information eg calories per serving.

You could extend this to the snacks in students’ bags. Are they as healthy as they think?

127. How to save money

A nice easy question to start the term with:

You go to the supermarket to buy your favourite shower gel (or other product). It usually costs £2.99. You have three £1 coins ready, when you notice the price has temporarily been reduced to £1.

What is the most money you can save?

Hint: Think of future gain

Solution:
It’s not the obvious £1.99 saved – that is instant gratification.

It is actually better to buy 3 bottles:

Saving = Actual price x 3 – Reduced price x 3

Saving = £2.99 x 3 – £1 x 3 = £8.97 – £3 = £5.97

If you spent the whole £3 (which is one bottle plus one pence), you get a long term saving which is worth far more, for just 1p more.

Teaching the concept of delayed benefit is rather useful, especially if you are trying to encourage open investigations or looking at time spent on personal revision.