Algebra delivers the goods

The calculations behind fi lling our supermarket shelves are dizzyingly complex – but it all starts with the x and y problems you remember from school

- Michael Brooks

Nando’s put it succinctly on its Twitter feed last month: “The UK supply chain is having a bit of a mare right now.” Getting things onto supermarket shelves, through your letterbox or into a restaurant kitchen has certainly become problematic of late. It’s hard to know exactly where to pin the blame, though Covid and Brexit have surely played a part. What we can do is give thanks for algebra, because things would be so much worse without it.

It’s likely that you have mixed feelings about algebra. Even if you could manage it in school, you probably wondered why it was important. You might even feel that your scepticism has been vindicated: chances are you have never used algebra in your post-school life. But that doesn’t mean algebra is useless. Whether it’s supermarket groceries, a new TV or a parcel, they all reach your home through some attempt to solve an equation. Algebra is the maths that delivers.

Algebra has been around for millennia. The word comes from the Arabic word al-jabr in the title of a ninth-century book on calculation. It is, essentially, the art of finding unknown numbers, given certain others. The hidden factor was usually referred to in Latin as the cossa, or “ thing ”, and so algebra was often known as the “ cossick art”: the art of the thing.

Until the 16th century, everything was written out in words. An early student of the cossick art might find themselves face to face with something like the following: two men are leading oxen along a road and one says to the other: “Give me two oxen and I’ll have as many as you have.” Then the other said: “Now you give me two oxen and I’ll have double the number you have.” How many oxen were there and how many did each have?