Heuristics to highlight

Act it out, Draw a diagram, Restate the problem in another way, Aim for sub-goals.

‘1 in 100 million chance: 6904 wins top two prizes in 4-D draw’ was the title of a news report on page H1 of The Straits Times Thursday 28 June. Is this probability correct? (The 4-D is a popular Singaporean gambling game which gives 23 prizes for 4-digit sequences obtained from 0000 to 9999. Repeats are allowed.)