The number on the bakery board

Text: an original contemporary consumer-column-style practice extract.

The bakery board announced HALF PRICE above a tray of cakes. Beneath it, smaller writing showed that a cake had been reduced from four pounds to two. I remembered buying the same size cake there for two pounds the previous week. The arithmetic on the board could be correct without describing a saving against the price familiar to me.

I asked which price had been halved. The assistant said the cakes had cost four pounds during a special event the day before. That explained the comparison and changed what I took from it. A visitor who had paid four pounds yesterday was seeing a real reduction. I was being offered the price I had already expected. We could read one board accurately and still have different reasons to feel pleased.

I bought a cake because I wanted one and considered two pounds reasonable. I did not buy it to collect half of an imaginary bargain. The large fraction drew my eye; the smaller explanation made the offer intelligible. Before celebrating a reduction, I now want to know the starting point from which it has been measured.

In this extract, the writer tries to encourage readers to look beyond a prominent discount figure.

Evaluate how successfully this is achieved. Support your views with detailed reference to the extract.