As we all know - or at least have been told often enough - declining levels of numeracy are the fault of trendy teaching methods. Those who doubt this should note the example of alumnus to be proud of No 89, Conservative whip Anthony Coombs, whose difficulties with numbers led to the Government "defeat" in the Commons last week. Mr Coombs was educated at those well known hotbeds of way-out educational methods, Charterhouse School and Worcester College, Oxford.