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Decimal Time

Stage: 3 Challenge Level: Challenge Level:2 Challenge Level:2

Congratulations to all of you who correctly gave the solution to this problem. There are too many of you to list here.

Harry of CPS was the first to send in a correct answer.

In decimal time the time only goes up to 10 so halfway through our day it is 12.00 and halfway through their day it is 5.00

A team from Oatlands Junior School went on to explain why 15:43 our time is 6:54 French Decimal Time.

In one UK day there are24 hours, but for the French time there are10 units of time.
And also for 1440 minutes the French equivalent would be 1000 French mins.
1 minute (English)= 1000 minutes (French)/ 1440 which was 0.6944.

They go on to work out how many minutes past midday (5:00 French Decimal Time) is equivalent to 15:43

The English clock moved 3hrs 43mins (223minutes) We multiplied 0.6944 by 223mins to get the French equivalent which was 154.86 French minutes. So the French clock moved 154.86 French minutes to get to 6:54.


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. More information on many of our other activities can be found here.
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