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Converting time intervals

Part of MathsTimeYear 4

Units of time

4 different types of measuring time: analogue clock, digital clock, calendar and an hour glass with sand.

The ing of time is a big part of our life.

You're born on a particular day of a month, in a year. We celebrate birthdays every year we get older.

At school, there are set times for registration, lunch, breaks and home time.

There are lots of different units of time: seconds, minutes, hours, days, weeks, months and years.

We use units of time to say when an event happens, or to measure time between events.

4 different types of measuring time: analogue clock, digital clock, calendar and an hour glass with sand.
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Activity: Converting time intervals

Complete this interactive activity to learn more about this topic and then put your knowledge to the test.

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Equivalent time units

It's important to know the value of these different measures of time and be able to convert them to find equivalent (equal in value) time intervals.

Here is a handy conversion guide:

Grid with 2 columns and 10 rows converting time. Reading rows from left to right, 60 seconds - 1 minute, 60 minutes - 1 hour, 24 hours - 1 day, 7 days - 1 week, 365 days 1 year, 52 weeks - 1 year, 10 years - 1 decade, 100 years - 1 century and 1000 years 1 millennium.

Every four years is a leap year. Instead of having 365 days, leap years have 366 days.

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Weeks and years

Let’s use this table to work out how many weeks there are in 3 years.

A girl called Lucy, looking thoughtful and standing next to a grid with 2 columns and 4 rows. Top row is headings weeks and years. Reading across each row is 52 - 1, 102 - 2 and 154 - 3.

First, look in the 'Years' column to find 3 years.

Then, read across to see how many weeks are in the ‘Weeks’ column. It shows there are 154 weeks in 3 years.

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Converting time intervals

When you know the equivalent time facts, you can use these to convert times.

Bar models are very useful to help with conversions.

Let's look at a question.

How many minutes are there in \(\frac{1}{3}\) of an hour?

There are 60 minutes in an hour, so let’s break 60 minutes into thirds using a bar model.

An Afro-Caribbean boy called Kevin who wears glasses and a green T-shirt. he is pointing to a grid with w rows. Top row says 60 minutes bottom row is split into 3 units each saying 20 minutes.

You can now see that \(\frac{1}{3}\) of an hour is  20 minutes.

Let's try another question.

How many months are there in 3 years and 4 months?

There are 12 months in one year. To find the number of months in 3 years, multiply 12 by 3.

12 × 3 = 36

A boy called Amir wearing a white rumaal and shirt. He is pointing to a grid with 2 rows. Top row says 36 months, bottom row is split into 3 units, each saying 12 months.

Now add the remaining 4 months to 36 to find the total.

36 + 4 = 40

So, 3 years and 4 months is the same as 40 months.

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Example 1

Many time problems need you to convert the units so they are all the same.

A house with a garage attached next to a calendar showing the year 2024.

The Henderson family have lived in their house for 140 days. The Johnson family have lived in their house for 22 weeks. Which family has lived in their house for longer?

To compare them, convert them to the same units, either days or weeks.

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Example 2

When you convert seconds to minutes, or minutes to hours, you can calculate with the number 60.

Patrick who has brown curly hair and wears a hearing aid, is smiling and holding up a stop watch for everyone to see.

How many seconds are there in 5 and a half minutes?

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More on Time

Find out more by working through a topic