Skip over navigation
17s and 23s
Age 11 to 14
ShortChallenge Level 
How many 2010-digit numbers are there in which every pair of consecutive digits forms a two digit number that is divisible by $17$ or $23$?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.
You may also like
Consecutive Numbers
An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.
Days and Dates
Investigate how you can work out what day of the week your birthday will be on next year, and the year after...