When the minutes add up to less than 60, we simply add the minutes together and the hours together.

Steps to Add Time

1. Add the minutes first
2. Add the hours next
3. Write the answer in hours and minutes

Worked Example

A pupil spends 2 hours 25 minutes doing homework and 3 hours 15 minutes reading. What is the total time spent?

So, the pupil spends 5 hours 40 minutes in total.

When the minutes add up to 60 or more, we must convert the extra minutes into hours.

Steps to Add With Regrouping

1. Add the minutes
2. If minutes are 60 or more, divide by 60 to get extra hours
3. Write the remaining minutes
4. Add the extra hours to the hours column
5. Write the final answer

Worked Example

A bus journey takes 3 hours 45 minutes, then another 4 hours 35 minutes. What is the total travel time?

80 minutes = 1 hour 20 minutes

The bus travels for 8 hours 20 minutes in total.

When the minutes in the second time are not more than the minutes in the first time, we subtract directly.

Steps to Subtract Time

1. Subtract the minutes first
2. Subtract the hours next
3. Write the answer in hours and minutes

Worked Example

A film started at 6:25 pm and ended at 5:15 pm. How long was the film?

The film lasted 1 hour 10 minutes.

When the minutes we need to subtract are more than the minutes we have, we must borrow 1 hour from the hours column.

Steps to Subtract With Regrouping

1. Check if minutes to subtract are more than minutes we have
2. If yes, take 1 hour (60 minutes) from the hours
3. Add 60 to the minutes
4. Subtract the minutes
5. Subtract the hours (remember to reduce the hours by 1)
6. Write the answer

Worked Example

A lesson started at 3:15 pm and ended at 1:45 pm. How long did the lesson last?

We cannot subtract 45 from 15, so we borrow 1 hour:

The lesson lasted 1 hour 30 minutes.

Example 1: Adding Times

Amina washes clothes for 1 hour 20 minutes and sweeps the house for 1 hour 35 minutes. How much time does she spend on both activities?

Amina spends 2 hours 55 minutes on both activities.

Example 2: Finding Duration

A train leaves Tanga at 06:00 and arrives in Dodoma at 17:45. How long does the journey take?

The journey takes 11 hours 45 minutes.

• 60 minutes = 1 hour
• When adding time: if minutes are 60 or more, convert to hours
• When subtracting time: if minutes are not enough, borrow 1 hour (60 minutes) from the hours column
• Always write answers in hours and minutes

In Tanzania, this skill is very useful when travelling by bus. For example, if a bus leaves Dar es Salaam at 8:00 in the morning and the journey to Morogoro takes 3 hours 45 minutes, a student can calculate that the bus will arrive at 11:45 am. This helps in planning when to wait at the bus station and when to inform family members about arrival times.