Stage: 2 Challenge Level: 
On a digital $24$ hour clock, at certain times, all the digits are consecutive (in counting order). You can count forwards or backwards.
For example, 1:23 or 5:43 .
How many times like this are there between midnight and 7:00?
How many are there between 7:00 and midday?
How many are there between midday and midnight?
Practical Activity. Combinations. Working systematically. Interactivities. Addition & subtraction. Multiplication & division. Visualising. Investigations. Factors and multiples. Time.
Published January 2000.
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