5th Grade Maths: Adding and Subtracting Time Intervals (Term 1 Chapter 5)

Time | Use Addition and Subtraction in Finding Time Interval | 5th Maths
5th Maths : Term 1 Unit 5 : Time

Use addition and subtraction in finding time interval

Addition

Example

Add: 4 hours 30 minutes and 2 hours 45 minutes

75 minutes = 1 hour 15 minutes
Time Addition Calculation

7 Hour 15 minutes

Example

Krishna goes to his village. He travels 4 hours 35 minutes in bus and 1 hour 55 minutes in two wheeler. What is his total time of travel?

Krishna Travel Time Calculation

$\therefore$ Kirshna travels totally for 6 hour 30 minutes

90 minutes = 60+30 minutes
60 minutes = 1 hour
30 minutes = 30 minutes
$\therefore$ 5+1 = 6 hour 30 minutes

Subtraction

Example

Subtract : 3 hours 45 minutes from 5 hours 30 minutes

Time Subtraction Borrowing
We can’t Subtract 45 minutes from 5 hours 30 minutes so we change the 5 hours in to (60 + 30) 90 minutes and subtract 45 minutes from 90 minutes. We can get 45 minutes.
When we subtract 3 hours from 4 hours balance is 1 hour
Example

Ram works on his Computer from morning 10' O Clock to Evening 3.30. How long does he work on his computer?

Ram work on his Computer at Evening = 3 Hours 30 Minutes

His work at Morning = 10 Hours 00 Minutes

AM PM Time Interval Calculation
Subtract from a.m. to p.m., we add 12 hours.
Add 3.30 hours + 12 hours we can get 15:30

$\therefore$ Ram works 5 hours 30 minutes on his computer

Example: School Schedule
School Time Table

(i) Find the time interval between First bell and morning break.

Calculation 1

The time interval between First bell and morning break is 2 Hours.

(ii) Find the time interval between the time of class starting and the time of morning break.

Calculation 2

The time interval between class starting time and morning break ending time is 1 hour 40 minutes.

We can’t subtract 30 minutes from 10 minutes so we convert to hour into minutes 1 hours to 60 minutes and add.
60+10 = 70 now we subtract 30 minutes from 40 we can get 1 hour 40 minutes.

(iii) Find the total time from starting of morning class to Closing of Afternoon class.

Calculation 3
Add 12 hours, 4.10 + 12.00 = 16 Hours + 10 minutes

The total time from starting of morning class to closing of afternoon class is 6 hours 40 minutes.

Try this

Find the time interval between starting of afternoon class and closing of evening class.

Calculation 4

Subtract from am to pm, we add 12 hours and then subtract the a.m time.