9654 /www/nrich/html/content/id/9654/ 10 0000-00-00T00:00:00 <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0">The key to solving these problems is to notice patterns or properties. Organising your work in a systematic way will allow you to notice what might not otherwise be obvious.</mdoxml> 2 3 0 0 0 0 0 Header for 9653