If it takes four men one day to build a wall, how long does it take
60,000 men to build a similar wall?
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.
Here's a chance to work with large numbers...
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?
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
These two challenges will test your time-keeping!
Nirmala and Riki live 9 kilometres away from the nearest market.
They both want to arrive at the market at exactly noon. What time
should each of them start riding their bikes?
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?
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.
In this version of the story of the hare and the tortoise, the race
is 10 kilometres long. Can you work out how long the hare sleeps
for using the information given?
How many times in twelve hours do the hands of a clock form a right
angle? Use the interactivity to check your answers.
Do you know the rhyme about ten green bottles hanging on a wall? If
the first bottle fell at ten past five and the others fell down at
5 minute intervals, what time would the last bottle fall down?
Can you rank these sets of quantities in order, from smallest to largest? Can you provide convincing evidence for your rankings?
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.
My measurements have got all jumbled up! Swap them around and see
if you can find a combination where every measurement is valid.
Alice's mum needs to go to each child's house just once and then
back home again. How many different routes are there? Use the
information to find out how long each road is on the route she
Use the clocks to investigate French decimal time in this problem.
Can you see how this time system worked?
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?
This article explains how Greenwich Mean Time was established and in fact, why Greenwich in London was chosen as the standard.
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...
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?
The pages of my calendar have got mixed up. Can you sort them out?
In this matching game, you have to decide how long different events take.
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
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?
Not everybody agreed that the Third Millennium actually began on January 1st 2000. Find out why by reading this brief article.
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.
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?
These clocks have only one hand, but can you work out what time
they are showing from the information?
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?
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?
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?
What is the date in February 2002 where the 8 digits are
palindromic if the date is written in the British way?
Astronomy grew out of problems that the early civilisations had. They needed to solve problems relating to time and distance - both mathematical topics.
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
This investigation explores using different shapes as the hands of
the clock. What things occur as the the hands move.
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?
Two trains set off at the same time from each end of a single
straight railway line. A very fast bee starts off in front of the
first train and flies continuously back and forth between the. . . .
My cousin was 24 years old on Friday April 5th in 1974. On what day
of the week was she born?
During the third hour after midnight the hands on a clock point in
the same direction (so one hand is over the top of the other). At
what time, to the nearest second, does this happen?
Use the information to work out the timetable for the three trains
travelling between City station and Farmland station.
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.?
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.
How many of this company's coaches travelling in the opposite
direction does the 10 am coach from Alphaton pass before reaching
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.
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?
Calendars were one of the earliest calculating devices developed by civilizations. Find out about the Mayan calendar in this article.