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MA08-02 Maths Coming soon

Calculating with time

MA08-02

This lesson is coming soon.

In this lesson

Convert a time given in hours and minutes to and from a decimal number of hours, convert between the 12-hour and 24-hour clock, and calculate a time interval.

What it covers

  • Converting a time given in hours and minutes into a decimal number of hours, and back again - specifically why the minutes have to be divided by 60, not written as decimal digits
  • Converting between 12-hour clock notation (am/pm) and 24-hour clock notation
  • Calculating a time interval between two given times, including intervals that cross an hour boundary
  • The basic relationships between units of time (60 seconds in a minute, 60 minutes in an hour, 24 hours in a day) as needed to support the conversions above

Key words

For: Cambridge IGCSE 0580, Edexcel IGCSE 4MA1

On the specification

BoardSpecStatement
Cambridge IGCSE 0580C1.15Calculate with time: seconds (s), minutes (min), hours (h), days, weeks, months, years, including the relationship between units.
Cambridge IGCSE 0580E1.15Calculate with time: seconds (s), minutes (min), hours (h), days, weeks, months, years, including the relationship between units.
Edexcel IGCSE 4MA1F1.10CUnderstand and carry out calculations using time, and carry out calculations using money, including converting between currencies
Edexcel IGCSE 4MA1F4.4BCalculate time intervals in terms of the 24-hour and the 12-hour clock
For teachers

This GCSE Maths lesson teaches calculating with time. By the end, students should be able to convert a time given in hours and minutes to and from a decimal number of hours, convert between the 12-hour and 24-hour clock, and calculate a time interval. It works through three worked examples and the mistakes examiners report.