This month there is a Friday the thirteenth and this year there are three. Can you explain why every year must contain at least one Friday the thirteenth?

A bus route has a total duration of 40 minutes. Every 10 minutes, two buses set out, one from each end. How many buses will one bus meet on its way from one end to the other end?

A train leaves on time. After it has gone 8 miles (at 33mph) the driver looks at his watch and sees that the hour hand is exactly over the minute hand. When did the train leave the station?

Every day at noon a boat leaves Le Havre for New York while another boat leaves New York for Le Havre. The ocean crossing takes seven days. How many boats will each boat cross during their journey?

Anne completes a circuit around a circular track in 40 seconds. Brenda runs in the opposite direction and meets Anne every 15 seconds. How long does it take Brenda to run around the track?

Use the clocks to investigate French decimal time in this problem. Can you see how this time system worked?

Which segment on a digital clock is lit most each day? Which segment is lit least? Does it make any difference if it is set to 12 hours or 24 hours?

I found these clocks in the Arts Centre at the University of Warwick intriguing - do they really need four clocks and what times would be ambiguous with only two or three of them?

At the time of writing the hour and minute hands of my clock are at right angles. How long will it be before they are at right angles again?

Sometime during every hour the minute hand lies directly above the hour hand. At what time between 4 and 5 o'clock does this happen?

Read this article to find out the mathematical method for working out what day of the week each particular date fell on back as far as 1700.

Calendars were one of the earliest calculating devices developed by civilizations. Find out about the Mayan calendar in this article.

Great Granddad is very proud of his telegram from the Queen congratulating him on his hundredth birthday and he has friends who are even older than he is... When was he born?

Galileo, a famous inventor who lived about 400 years ago, came up with an idea similar to this for making a time measuring instrument. Can you turn your pendulum into an accurate minute timer?

On a digital clock showing 24 hour time, over a whole day, how many times does a 5 appear? Is it the same number for a 12 hour clock over a whole day?

How many times in twelve hours do the hands of a clock form a right angle? Use the interactivity to check your answers.

A game for two or more players that uses a knowledge of measuring tools. Spin the spinner and identify which jobs can be done with the measuring tool shown.

Can you create a story that would describe the movement of the man shown on these graphs? Use the interactivity to try out our ideas.

Use the interactivity to move Mr Pearson and his dog. Can you move him so that the graph shows a curve?

Two engines, at opposite ends of a single track railway line, set off towards one another just as a fly, sitting on the front of one of the engines, sets off flying along the railway line...

This article explains how Greenwich Mean Time was established and in fact, why Greenwich in London was chosen as the standard.

If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?

Noticing the regular movement of the Sun and the stars has led to a desire to measure time. This article for teachers and learners looks at the history of man's need to measure things.

What can you say about when these pictures were taken?

Can you order pictures of the development of a frog from frogspawn and of a bean seed growing into a plant?

What is the date in February 2002 where the 8 digits are palindromic if the date is written in the British way?

Can you rank these sets of quantities in order, from smallest to largest? Can you provide convincing evidence for your rankings?

Can you place these quantities in order from smallest to largest?

Can you rank these quantities in order? You may need to find out extra information or perform some experiments to justify your rankings.

A paradox is a statement that seems to be both untrue and true at the same time. This article looks at a few examples and challenges you to investigate them for yourself.

My cousin was 24 years old on Friday April 5th in 1974. On what day of the week was she born?

If Tom wants to learn to cook his favourite supper, he needs to make a schedule so that everything is ready at the same time.

Can you put these times on the clocks in order? You might like to arrange them in a circle.

How far have these students walked by the time the teacher's car reaches them after their bus broke down?

In this matching game, you have to decide how long different events take.

Stuart's watch loses two minutes every hour. Adam's watch gains one minute every hour. Use the information to work out what time (the real time) they arrived at the airport.

The pages of my calendar have got mixed up. Can you sort them out?

On a digital 24 hour clock, at certain times, all the digits are consecutive. How many times like this are there between midnight and 7 a.m.?

Can you put these mixed-up times in order? You could arrange them in a circle.

This article for teachers suggests ways in which dinosaurs can be a great context for discussing measurement.

Use your knowledge of angles to work out how many degrees the hour and minute hands of a clock travel through in different amounts of time.

Look at the changes in results on some of the athletics track events at the Olympic Games in 1908 and 1948. Compare the results for 2012.

Measure problems at primary level that may require determination.

Measure problems for inquiring primary learners.

Chandrika was practising a long distance run. Can you work out how long the race was from the information?

Measure problems for primary learners to work on with others.

Measure problems at primary level that require careful consideration.

This article for teachers suggests ideas for activities built around 10 and 2010.

Investigate the different distances of these car journeys and find out how long they take.

My measurements have got all jumbled up! Swap them around and see if you can find a combination where every measurement is valid.