Åk 6–9
 
English/فارسی
2.8 Time in Decimal Form
How much time is 3.25 h in hours and minutes?

When we calculate time in decimal form, we need to think closely.
3.25 h is NOT the same thing as 2 hours and 25 minutes. Why?







60 min =
60

60
h = 1h
30 min =
30

60
=
1

2
h =0.5 h
15 min =
15

60
=
1

4
h =0.25 h

In the picture to the right, we can clearly see that 0.25 h = 15 minutes. So 3.25 h = 3 hours and 15 minutes. The reason for this is that there is 60 minutes in 1 hour.

How do we then think when we work with time in decimal form?

Let’s look at a few more examples:




Example 1

How do you express 2 hours and 18 minutes in decimal form?

18 min =
18

60
h = 0.3 h






2 hours and 18 minutes = 2.3 h




Example 2

How do you write 4.6 h in hours and minutes?

4.6 h = 4 hours and (0.6 · 60) min = 4 hours and 36 min

4.6 h = 4 hours and 36 minutes