Remember: Smaller units (seconds) need many of them to make a larger unit (minutes or hours).

To change seconds into minutes, divide by 60.

Example 1

How many minutes are there in 720 seconds?

Solution

1 minute = 60 seconds

$720 \div 60 = 12$

So, 720 seconds = 12 minutes.

Example 2

Convert 180 seconds into minutes.

Solution

$180 \div 60 = 3$

So, 180 seconds = 3 minutes.

To change minutes into hours, divide by 60.

Example 3

A pupil takes 150 minutes to complete a project. Convert this into hours.

Solution

1 hour = 60 minutes

$150 \div 60 = 2 \text{ hours } 30 \text{ minutes}$

So, 150 minutes = 2 hours 30 minutes.

To change hours into minutes, multiply by 60.

Example 4

Convert 5 hours into minutes.

Solution

1 hour = 60 minutes

$5 \times 60 = 300$

So, 5 hours = 300 minutes.

To change seconds directly to hours, we divide by 3600. Alternatively, we can convert seconds to minutes first, then minutes to hours.

Example 5

How many hours are there in 7200 seconds?

Solution

Method 1: Direct conversion

1 hour = 3600 seconds

$7200 \div 3600 = 2$

So, 7200 seconds = 2 hours.

Method 2: Two-step conversion

First: 7200 ÷ 60 = 120 minutes Then: 120 ÷ 60 = 2 hours

Example 6

Convert 9000 seconds into hours and minutes.

Solution

Step 1: Convert seconds to minutes $9000 \div 60 = 150 \text{ minutes}$

Step 2: Convert minutes to hours $150 \div 60 = 2 \text{ hours } 30 \text{ minutes}$

So, 9000 seconds = 2 hours 30 minutes.

To change hours into seconds, multiply by 3600.

Example 7

How many seconds are there in 3 hours?

Solution

1 hour = 3600 seconds

$3 \times 3600 = 10800$

So, 3 hours = 10,800 seconds.

• Small → Large: Divide (seconds → minutes, minutes → hours)
• Large → Small: Multiply (hours → minutes, minutes → seconds)
• Remember: 60 seconds = 1 minute, 60 minutes = 1 hour, 3600 seconds = 1 hour

When solving time conversion problems:

1. Identify the units you are converting from and to
2. Remember the relationship between the units
3. Decide whether to multiply or divide
4. Check your answer by reversing the calculation

In Tanzania, knowing how to convert time units helps with daily activities. For example, if a bus journey from Dar es Salaam to Dodoma takes 9 hours and you want to know how many minutes that is, you multiply 9 × 60 = 540 minutes. This helps you plan when to start your journey and estimate arrival times.