Time, calendars and ages
Recognise the model, justify the rule and solve independently.
IKMC Grades 7-8 - Selected Topics
Convert all durations to one unit before adding or subtracting, and explain why 0.5 hours is 30 minutes, not 50.
Explain why only the remainder on dividing the number of days by 7 decides the day of the week.
Explain why the difference between two ages never changes, while their ratio usually does.
Use the speeds of the clock hands, 6 degrees and 0.5 degrees per minute, to find the angle between them at any time.