Driving past Bristol on the M5 this evening, there was one of the time and distance signs lit up, telling me that it was 40 miles to the Swindon junction on the M4 and that my journey time would be 34 minutes. That works out at an average speed of 85mph! So, temperature was -2, road was busy and viz was no better than average but the motorway signage is telling me I can drive at 85mph. Am I missing something?

Brilliant! I'm gonna watch out for those. You should get a passenger take a photo of that and then if you get a ticket, I think you have some ammo

Actually that calculates as 70.58 mph or the speed limit in other words. 40 * 60/34 = 70.588... Sorry your math went wrong somewhere

No....his maths went wrong somewhere. This isn't an American forum. Actually though...would this not be more accurately termed as Arithmetic? Not entirely sure about that. Your calculation was spot on though. For a handy Distance/Speed/Time calculator click here

No wonder this country is in such a state - multiplication / division now counts as higher maths? Multiplication and division were tested at 11+ and then GCSE. It was calculus that was left to further Maths... Sidicks

I'm not entirely sure, but I think it would be true to say that mathematics covers the whole field of number-related activity, so arithmetic is a branch of maths.

This is true, but Arithmetic is Maths in in its most basic form, pretty much confined to adding, subtracting, multiplying and dividing. Arithmetic was treated as a separate O Grade exam to Maths when i was at school, although both were obviously taught together. It was also much easier, as my grades proved - A & C respectively.