Thanks Kenjo. It's definately not gas but will work on your theory.
Sue
May 2012
Even in 1970s dials were calibrated in degr Fahrenheit or centigrade Sue ,Maybe dial has been replaced with wrong one. Unless of course your oven is a GAS oven these are calibrated 1 to6. If electric the temps roughly would be 250C top temp divided equally in 6 increments