What Time Will It Finish?

Teaching finish times

Prerequisites: elapsed time with hops, and number bonds to 60.

Suggested sequence (20 min)

1. Recap hops: Show start and finish and ask “How long?”, then flip it: “Start and how long, what’s the finish?”
2. Add hours first: Only whole hours: 2:30 + 2 hours.
3. Add minutes through the hour: Use number bonds to 60 to get to the next hour.
4. Finding the start: Challenge: “It finishes at 5:15 and takes 40 minutes. When did it start?” (Count back.)

Common misconceptions

• Going over 60. 3:40 + 45 is not 3:85. Minutes wrap at 60.
• Forgetting the hour changes. After hopping past :00, the hour number goes up.
• 12-hour clock wrap. After 12:59 comes 1:00.

Questions to ask

• “How many minutes to the next whole hour?”
• “How could you check by counting back?”

Curriculum links

UK Year 3–4: calculate durations and convert between hours and minutes. US CCSS 3.MD.1: solve word problems involving addition and subtraction of time intervals in minutes. 4.MD.2: word problems involving intervals of time.

What your child is learning

Your child is learning to work out when something will finish by adding hours and minutes to a start time.

Why it can feel tricky

• Minutes go up to 60, not 100.
• The hour changes in the middle of the sum.

Easy ways to help at home

• “We leave at 8:40 and it’s a 35-minute drive. When will we arrive?”
• Set a timer and predict the finish time.
• Work out when the TV programme will end.
• Keep it short and playful. 2 or 3 minutes at a time is plenty.

Try this: “It’s 4:45. What time will it be in 30 minutes?” (5:15)