Números negativos: ¿cuál es mayor? ¿cuál menor?

En el blog Mathematics under the Microscope aparece una anécdota sobre un sorteo tipo rasca y gana en Inglaterra. El juego consistía en rascar una ventana en la que aparecían algunos números representando grados de temperatura, se ganaba un premio si dos de los números (temperatura) que aparecían en la ventana eran menores a la temperatura mostrada en el boleto. El problema fue que algunas personas no podían entender que -6 es mayor a -8 por ejemplo. La empresa dueña del sorteo tuvo que retirar la lotería de las tiendas. De the Newsletter of The London Mathematical Society (no. 365 Dec 2007) les pongo la noticia en inglés:

LOTTERY SCRATCHCARD

From the Manchester Evening News 3 Nov 2007

A Lottery scratchcard – the Cool Cash game – was taken out of shops yesterday after some players failed to grasp whether or not they had won.

To qualify for a prize, users had to scratch away a window to reveal a temperature lower than the figure displayed on each card. As the game had a winter theme, the temperature was usually below freezing. But the concept of comparing negative numbers proved too difficult for some. Camelot received dozens of complaints on the first day from players who could not understand how, for example, –5 is higher than –6.

Tina Farrell, from Levenshulme, called Camelot after failing to win with several cards. The 23-year-old, who said she had left school without a maths GCSE, said: "On one of my cards it said I had to find temperatures lower than –8. The numbers I uncovered were –6 and –7 so I thought I had won, and so did the woman in the shop. But when she scanned the card the machine said I hadn't. I phoned Camelot and they fobbed me off with some story that –6 is higher – not lower – than –8 but I'm not having it. I think Camelot are giving people the wrong impression – the card doesn't say to look for a colder or warmer temperature, it says to look for a higher or lower number. Six is a lower number than 8. Imagine how many people have been misled."

A Camelot spokeswoman said the game was withdrawn after reports that some players had not understood the concept.