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Legs Eleven

Take any four digit number. Move the first digit to the end and move the rest along. Now add your two numbers. Did you get a multiple of 11?

How Many Miles to Go?

How many more miles must the car travel before the numbers on the milometer and the trip meter contain the same digits in the same order?

Farey Sequences

There are lots of ideas to explore in these sequences of ordered fractions.

Reverse Ages

Age 11 to 14 Short Challenge Level:


On Brian's 14th birthday, his father was 41.
Brian noticed that his age was the reverse of his father's age.

How old will Brian be the next time his age is the reverse of his father's age?



This problem is adapted from the World Mathematics Championships
You can find more short problems, arranged by curriculum topic, in our short problems collection.
The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.
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