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Maths In Games

How timers teach time and decimals

Use countdowns, lap times and speed challenges to practise seconds, minutes and decimal notation.

Quick answer

Timers help children learn time by showing seconds, minutes, and hours pass, and they teach decimals by showing how time can be broken into parts like 0.5 minutes or 0.25 seconds.

Learning outcome

By the end of this page, you will understand how timers help you learn to read time in minutes and seconds, and how decimals show parts of time. Success signs:
  • You can tell the time to the minute and second
  • You can write time as decimals like 0.5 minutes or 0.25 seconds
  • You can use a timer to measure how long tasks take
  • You can compare times using decimals

Why this matters

Timers are used in many games and real-life situations. When you play a racing game, you might see lap times. When you're cooking, you might use a timer for 3 minutes and 45 seconds. When you're playing football, you might count how many seconds are left in a game. Timers teach us that time is made up of smaller parts, and we can show those parts using decimals.

How it works

Timers count down from a set time, showing how much time is left. When a timer shows 3 minutes and 45 seconds, it means:
  • 3 minutes = 3 × 60 = 180 seconds
  • 45 seconds = 45 seconds
  • Total = 180 + 45 = 225 seconds
We can also write 3 minutes and 45 seconds as a decimal. If we say 3.75 minutes, that means:
  • 3 minutes = 3
  • 45 seconds = 45 ÷ 60 = 0.75 minutes
  • So 3 minutes and 45 seconds = 3.75 minutes

Examples you can see

Let's imagine you're playing a video game where you have to complete a level. Your timer shows 2 minutes and 15 seconds. Example 1: What is 2 minutes and 15 seconds in seconds?
  • 2 minutes = 2 × 60 = 120 seconds
  • 15 seconds = 15 seconds
  • Total = 120 + 15 = 135 seconds
Example 2: What is 2 minutes and 15 seconds in decimal minutes?
  • 2 minutes = 2
  • 15 seconds = 15 ÷ 60 = 0.25 minutes
  • So 2 minutes and 15 seconds = 2.25 minutes
Example 3: If you have a timer showing 1 minute and 30 seconds, how many seconds is that?
  • 1 minute = 1 × 60 = 60 seconds
  • 30 seconds = 30 seconds
  • Total = 60 + 30 = 90 seconds
Example 4: How do you write 1 minute and 30 seconds as a decimal?
  • 1 minute = 1
  • 30 seconds = 30 ÷ 60 = 0.5 minutes
  • So 1 minute and 30 seconds = 1.5 minutes

Try it as a mini adventure

Adventure: Race Time Challenge You are part of a team racing to finish a treasure hunt. You have a timer to measure how long each part takes. First part: You run for 1 minute and 15 seconds.
  • How many seconds is that? 75 seconds
  • How do you write it as a decimal? 1.25 minutes
Second part: You climb a wall for 45 seconds.
  • How many seconds is that? 45 seconds
  • How do you write it as a decimal? 0.75 minutes
Third part: You solve a puzzle for 2 minutes and 30 seconds.
  • How many seconds is that? 150 seconds
  • How do you write it as a decimal? 2.5 minutes
Challenge: Add up all your times in seconds.
  • 75 + 45 + 150 = 270 seconds
Challenge: Add up all your times as decimals.
  • 1.25 + 0.75 + 2.5 = 4.5 minutes

Common mistakes

  • Mistake: Thinking 1 minute and 30 seconds = 1.30 minutes
    Why it happens: Mixing up decimal notation with time notation
    Fix: Remember that 30 seconds = 30 ÷ 60 = 0.5 minutes, so it's 1.5 minutes
  • Mistake: Adding minutes and seconds like 2 minutes + 45 seconds = 245 seconds
    Why it happens: Not converting minutes to seconds first
    Fix: Convert 2 minutes to seconds (2 × 60 = 120 seconds), then add 120 + 45 = 165 seconds
  • Mistake: Writing 30 seconds as 0.30 minutes
    Why it happens: Confusing decimal places with time
    Fix: 30 seconds = 30 ÷ 60 = 0.5 minutes

Parent and carer guide

Parents and carers can help by:
  • Using a kitchen timer to measure cooking tasks (like 2 minutes and 30 seconds)
  • Playing a game where you race to complete tasks and time them
  • Practising converting times to decimals using simple examples
  • Encouraging children to say times in both formats: "3 minutes and 45 seconds" and "3.75 minutes"
  • Helping children understand that decimals are parts of a whole, just like time
Don't worry if your child makes mistakes. It's normal to mix up time and decimal notation at first. Be patient and keep practising with fun examples like cooking, races, or games.

Practice questions

  1. How many seconds are in 1 minute and 15 seconds?
  2. How do you write 1 minute and 15 seconds as a decimal?
  3. How many seconds are in 2 minutes and 45 seconds?
  4. How do you write 2 minutes and 45 seconds as a decimal?
  5. How many seconds are in 3 minutes and 10 seconds?
  6. How do you write 3 minutes and 10 seconds as a decimal?
  7. How many seconds are in 45 seconds?
  8. How do you write 45 seconds as a decimal?
  9. How many seconds are in 1 minute and 30 seconds?
  10. How do you write 1 minute and 30 seconds as a decimal?
Answers:
  1. 75 seconds
  2. 1.25 minutes
  3. 165 seconds
  4. 2.75 minutes
  5. 190 seconds
  6. 3.17 minutes
  7. 45 seconds
  8. 0.75 minutes
  9. 90 seconds
  10. 1.5 minutes

FAQ

What is a timer?

A timer is a device that counts down from a set time to zero. It helps us know how much time is left for a task.

Why do we use decimals with time?

We use decimals with time to make it easier to add and compare times. For example, 2.5 minutes is easier to add to 1.25 minutes than 2 minutes and 30 seconds plus 1 minute and 15 seconds.

How do you convert seconds to minutes?

To convert seconds to minutes, divide the number of seconds by 60. For example, 45 seconds ÷ 60 = 0.75 minutes.

Can you use a timer for any activity?

Yes! You can use a timer for anything that takes time. Cooking, playing games, reading, running, or doing chores. Timers help us manage our time better.

How can I practice with my child?

Practice by timing simple tasks like brushing teeth (2 minutes), doing jumping jacks (1 minute), or cooking a simple recipe. Ask your child to convert the time to decimals and add up times.