Topic 4: Nella pratica: attività, materiale didattico, suggerimenti e idee

In Practice: Activities, Teaching Material, Tips & Ideas

FRACTIONS AND ESTIMATIONS
Supermarkets are expected to provide information that will allow you to compare prices quickly and easily. However, you will probably have noticed that although the information is there, it’s still not that easy to compare prices.   Here are some of the different ways that supermarkets provide information that can make it harder:
– Displaying information for two adjacent products in a different form, for example, one giving price per 100g and the other price per kg, or price per unit compared to price per weight.
– Not displaying price per 100g under any offers, for example, 3 for 2, or ‘buy one get one free’.
– Selling in certain units, but offering price comparisons in a different size, for example, yoghurts are often sold in 125g pots, but the price comparison will be per 100g. Cheese is often sold in 300g packets, but prices are per kg.
– Providing offers with ‘funny numbers’ that make it harder to divide and see what you’re getting for your money. Examples of this include ‘3 for euros 2’.
– Selling similar products in packs of different numbers of items or in different sizes, so that you can’t just compare the prices of the two packets. For example, supermarket own-brand cereal may come in a smaller box than a named brand, making a difference of a few cents  in the price look much bigger.
It’s fair to say that most people won’t be whipping out their calculator, or even their phones, to compare prices. After all, an offer’s always better value, isn’t it? But what about when you have two competing offers?
Using techniques like reducing fractions and estimating will help:

EXERCISE:       You can see two offers: ‘5 for  Euros 2’ and ‘Two packs of six for Euros 5’.  Which is better value?

In many places, sales taxes are added to the basic purchase prices of both goods and services.
For example, in many EU countries, value-added tax (VAT) is added to various items. Prices may be shown with or without taxes included, either to make the price look lower, or because some buyers may be able to claim back the tax, and therefore need to know the tax-free cost.
If you want to work out what you will have to pay, you may therefore need to work out sales tax quickly, and you may not have a calculator to hand.
The tax is usually a percentage so, it is important to know what it means

A pictogram is a special type of bar graph. Instead of using an axis with numbers, it uses pictures to represent a particular number of items. For example, you could use a pictogram for the data above about ages, with an image of a person to show the number of people in each category.