I am dyslexic with numbers. We used to have questions like that at school, (not in pre-decimal currency) but stuff like how long it takes a man to go somewhere in a car with half a gallon of petrol at 6 mph, 7 miles, how many times he refils, plus how much change he got when buying it, and if he set off at 6.30 when did he arrive? Every time i saw a question like that i put a dash next to it and moved onto the next one. You totally lost me there mate, completely. I could figure out how much you spend and the change, but when it comes to getting cash in largest denom coins, i could never do anything like that, far too complex. But i can tell you how many atoms are in 1 mole of carbon should you wish.