On the LearnEnglish Kids website you will find materials for practising numbers with all levels of young learners. Activities range from simple matching and spelling exercises to stories and worksheets to practise really big numbers. The topic also includes lots of fun games including a mind reading number game, a song to practise forming numbers and lots of maths activities. You can find the materials at http://www.britishcouncil.org/kids-topicsnumbers.htm.