Units of time

Teaching units of time

Prerequisites: times tables for 2, 5, 10 and (later) 60, 24 and 7; reading the clock to the hour and half hour.

Suggested sequence (20 min)

1. Feel the units: clap for 10 seconds, sit quietly for 1 minute. Ask “what could you do in 1 minute?”
2. Order them: children put unit cards from shortest to longest, then use the time ladder above to check.
3. Equivalences: build the chain: 60 seconds, 60 minutes, 24 hours, 7 days, 12 months.
4. Choose the unit: use “Which unit?” to discuss why seconds, minutes or hours fit each event.
5. Convert: use the “Change the units” tool and ask children to predict the answer before it is shown.

Common misconceptions

• “100 seconds in a minute”. Time is not base 10. Show a stopwatch passing 59 to 1:00.
• “All months have 30 days”. Use the knuckle rule or the rhyme “Thirty days hath September…”.
• Multiplying instead of dividing (or the reverse). Ask: “Will there be more minutes or more hours?”
• Thinking a year always has 365 days. Mention leap years (366).

Questions to ask

• “Would that take seconds, minutes or hours?”
• “Are there more minutes or more seconds in 3 hours? How do you know?”
• “How many hours are in a weekend?”

Retrieval tip: start each lesson with “Quick fire facts”: 60 seconds, 60 minutes, 24 hours, 7 days.

Curriculum links

UK Year 2: know the number of minutes in an hour and hours in a day. UK Year 3: know the number of seconds in a minute and days in each month, year and leap year. UK Year 4: convert between units of time (years, months, weeks, days, hours, minutes, seconds). US CCSS 3.MD.1: tell and write time and solve problems with time intervals in minutes; 4.MD.1: convert units of time within one system.

What your child is learning

Your child is learning the units we use to measure time: seconds, minutes, hours, days, weeks, months and years, how they fit together, and how to change one into another.

Why it can feel tricky

• Time does not use tens: it uses 60, 24, 7 and 12, so patterns are harder to see.
• Months have different lengths, which looks inconsistent.

Easy ways to help at home

• Time everyday jobs with a timer: getting dressed, brushing teeth, tidying up.
• Ask “Would that take seconds, minutes or hours?” about daily events.
• Use a calendar: count the days or weeks until a birthday or holiday.
• Learn “Thirty days hath September…” or the knuckle trick for month lengths.

Try this in the car: “The journey takes 2 hours. How many minutes is that?” (120!)