Time

By key stage 3, we should be focusing on the following skills related to time:

Year 7   to measure and record time in hundredths of a second and use time zones.

Year 8 to interpret fractions of a second appropriately and use timetables and time zones to calculate travel time.

However we are finding that many pupils struggle with basic skills such as telling the time and working out time intervals.

Century 100 years
Decade 10 years
Year 365 days or 266 days in a leap year

52 weeks and 1 (or 2) days

Month Between 28 and 31 days
Fortnight 2 weeks
Week 7 days
Weekend 2 days
Day 24 hours
Hour 60 minutes
Minute 60 seconds
Second 100 hundredths of a second

1000 milliseconds

Adding and Subtracting Time

Time is not metric and therefore many pupils struggle with working out time intervals.  Take these examples:

Jack goes out to play at 5:30 and his mother asks him to be back in 20 minutes for dinner.  What time is dinner?

This one is straight forward – just add 30 to 20 – Jack’s dinner is at 5:50 – or ten to six.

The chicken is put in the oven at 11:55 and will take an hour and 48 minutes to cook.  What time will it be ready?

Here many people start reaching for the calculator – but time questions don’t really work using a calculator.  Try breaking the question down into parts.

  1. Add the hour to the time the chicken goes into the oven – this gives us 12:55.
  2. We now have 48 minutes left.  Take 5 minutes off this to get us to 1pm – leaving 43 minutes.
  3. The chicken will be ready at 1:43pm.

Maths is Fun has a very useful page on this topic.

12 and 24 hour clocks

Children need to be able to tell the time using both analogue and digital clocks, and to switch between 12 and 24 hours.

http://www.mathsisfun.com/time.html

See Maths is Fun for some interactive sliders and more worked examples.

Time Zones

These can be really confusing to work out.  If you are lucky enough to be going abroad on holiday, talk to your child about what time zone the country is in (use the interactive map at timeanddate.com).  Often the hardest part is working out what this means for your journey.  Do you gain or lose time?

 

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