Friday, 20 March 2015

Real-World Maths vs. Classroom Maths - conspiring to confuse?

The 'real world' beyond our classroom walls often does little for the cause of helping students become mathematically confident and pragmatically 'numerate'. Beyond the common cultural messages about it being perfectly ok to be unable to do maths (whereas being unable to read, for example, is not ok,) there are numerous ways in which maths in the real world is disjointed from classroom maths.

Take, for instance, this current british road sign indicating the steepness of a hill:

Why is it, that although we have a statutory national curriculum in which everyone learns that gradients are given as single figure ratios of 'rise / run', this road sign flies in the face of that fact and gives the steepness as a percentage? A percentage is an appalling way to measure steepness. It is not immediately clear whether this sign would indicate a slope with a gradient of 0.1 or a slope at an angle of 10% of a right angle. Either way, it is a disconnect from the idea of gradient as it is learned in school.

Gambling odds are another example of classroom maths being mismatched from 'real-world' maths. (Of course, I am obliged here to say that I am not advocating that we should encourage students to gamble by teaching them about it. However, avoiding the topic in the classroom is not helping students to make informed choices about it later.) Again, following the national curriculum, probability is developed as a single number proportion - in this case, interchangeably fractions, decimals or (less frequently) percentages. When encountering betting odds in the real world, we are faced with a pair of numbers to interpret:

How do we make sense of this? Is this a fractional probability: 10 out of 1? Does it mean in ten races, the horse is likely to win once? Is the horse 10 times more likely to win than to lose? (None of these are correct!) Of course, I do not think that it is in the interests of the gambling industry to make the maths easy to understand for the 'consumer', and one could argue that this system preserves a cultural tradition of presenting gambling odds in this way.

Differences like these serve to fuel the notion that the language of classroom maths is not the same as the language of real-world maths. To students who are already inclined to think they cannot do maths, this surely reinforces the idea in their mind. If we really want to educate students to be pragmatically numerate in the 'real world', educating students in a different 'language' will not help!

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