Time is different to most calculations, because you use a number line instead of columns; that's because there the Maths is based on 60s not 100s!
Try some of these games to get warmed up:
http://www.bgfl.org/bgfl/custom/resources_ftp/client_ftp/ks2/maths/timetables/index.htm
http://www.maths-games.org/time-games.html
http://www.oswego.org/ocsd-web/games/StopTheClock/sthec5.html