I once visited an Israeli primary school in Jerusalem and looked around a classroom. It was much the same as any classroom in the UK, with desks, pots of crayons, bookshelves, and work displayed on walls. But something caught my attention with one set of arithmetic posters. Addition was not symbolised by the plus sign but by an upside-down letter T.
I asked the headteacher and learned that the tradition goes back to at least the 19th century and was a deliberate avoidance of a sign that otherwise looked like the Christian cross. Not all Israelis follow this convention, but it is common among the more orthodox Jews.
That intrigued me, as I don’t think many in the West would associate the plus sign with the cross. In fact, the sign of a cross has many different uses – a first aid kit, a kiss, a simple signature. The addition sign itself has nothing to do with Christian theology and much to do with how the Latin word “et” (and) was written. It would seem to take a lot of sensitivity for anyone to immediately link the addition sign to the Christian faith.
