Time, Measuring time Chapter Notes | Year 5 Mathematics IGCSE (Cambridge) - Class 5 PDF Download

Measuring Time

• Millisecond: A thousandth of a second (1/1000 second).
• Nanosecond: A thousand-millionth of a second (1/1,000,000,000 second).

Decimals are used to represent fractions of time units:

• Example: 0.5 hours = 30 minutes (since half of one hour is 30 minutes).
• Example: 0.5 minutes = 30 seconds (since half of one minute is 30 seconds).

Conversions between time units:

• 0.5 days = 12 hours.
• 1.5 hours = 90 minutes.
• 2.5 days = 60 hours.
• 2.5 minutes = 150 seconds.
• 330 seconds = 5.5 minutes.
• 1.5 days = 36 hours.
• 1.5 minutes = 90 seconds.
• 2.5 hours = 150 minutes.
• 108 hours = 4.5 days.
• 630 minutes = 10.5 hours.
• Estimation is used to predict the duration of events, such as a 100-meter sprint (seconds) or a marathon (hours).

Calculating Time Intervals

Method 1: 3 minutes (07:04 to 07:07) + 50 minutes (07:07 to 07:57) = 53 minutes.
Method 2: 56 minutes (07:04 to 08:00) - 3 minutes (07:57 to 08:00) = 53 minutes.
Example: From 07:57 to 10:04 (2 hours 7 minutes):
Method: 2 hours (07:57 to 09:57) + 7 minutes (09:57 to 10:04) = 2 hours 7 minutes.

Different methods may use different numbers of jumps on the number line, depending on how the interval is broken down (e.g., jumping to the nearest hour or minute).