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Each time you visit the NRICH site there will be some activities which are 'live'. This means we are inviting students to send us solutions, and we will publish a selection of them, along with each student's name and their school, a few weeks later. If you'd like to know more about what we're looking for, read this short article.
The last day for submitting solutions to these live problems is Monday 27 November.
The picture shows a lighthouse and some underwater creatures. Can you work out the distances between some of the different creatures?