[误] We have a match on single-numbered days of each month.

　　[正] We have a match on odd-numbered days of each month.

　　注：single 是“单一的，单个的”意思如：single-eyed(独眼的)，single-handed(独手的，单枪匹马的)等。而odd 才表示“单数的，奇数的”意思，如：odd houses(单号门牌的房子)，odd month(有三十天的月份)等。