Matematika Ria
Tambahkan ke favorit Tambahkan ke favorit
link Tautkan di sini
Beranda Matematika RiaBeranda








Hak cipta © 2009
MatematikaRia.com

Adding and Subtracting Time

Advice: Add or Subtract the hours and minutes separately. But you may need to do some adjusting if the minutes end up 60 or more, or less than zero!

Adding Times

Follow these steps:

  • Add the hours
  • Add the minutes
  • If the minutes are 60 or more, subtract 60 from the minutes and add 1 to hours

Easy example: What is 2:45 + 1:10 ?

Add the Hours: 2+1 = 3
Add the Minutes: 45+10 = 55
The minutes are ok, so the answer is 3:55

Hard example: What is 2:45 + 1:20 ?

Add the Hours: 2+1 = 3
Add the Minutes: 45+20 = 65
The minutes are 60 or more, so subtract 60 from minutes (65-60 = 5 Minutes) and add 1 to Hours (3+1 = 4 Hours) ... so the answer is 4:05

Subtracting Times

Follow these steps:

  • Subtract the hours
  • Subtract the minutes
  • If the minutes are negative, add 60 to the minutes and subtract 1 from hours.

(Note: the easiest way to add 60 to the negative minutes is to start with 60 and subtract the minutes)

Easy example: What is 4:10 - 1:05 ?

Subtract the Hours: 4-1 = 3
Subtract the Minutes: 10-5 = 5
The minutes are fine, so the answer is 3:05

Hard example: What is 4:10 - 1:35 ?

Subtract the Hours: 4-1 = 3
Subtract the Minutes: 10-35 = -25
The minutes are less than 0, so add 60 to Minutes (-25+60 = 60-25 = 35 Minutes) and subtract 1 from Hours (3-1 = 2 Hours) ... answer is 2:35