Last updated on July 28th, 2025
The mathematical operation of finding the difference between two time periods is known as the subtraction of hours and minutes. This process helps calculate durations, solve time-related problems, and manage schedules effectively.
Subtracting hours and minutes involves taking one time period from another. This requires careful attention to the units of hours and minutes, ensuring that minutes are subtracted correctly, even when borrowing is necessary.
The components involved in this operation are:
Hours: These are whole number units of time.
Minutes: These are fractional units of an hour, with 60 minutes making up one hour.
Borrowing: When the minutes in the minuend are less than those in the subtrahend, you borrow one hour (60 minutes) from the hours.
When subtracting hours and minutes, follow these rules:
Borrow when necessary: If the minutes in the minuend are less than those in the subtrahend, borrow an hour from the hours to add 60 minutes to the minuend's minutes.
Subtract minutes: Once borrowing is done, subtract the minutes of the subtrahend from those of the minuend.
Subtract hours: Subtract the hours of the subtrahend from those of the minuend.
The following are methods to subtract hours and minutes:
Method 1: Standard Method
To apply the standard method for subtracting hours and minutes, use these steps.
Step 1: Write the time periods with hours and minutes clearly labeled.
Step 2: If needed, borrow one hour from the hours column to the minutes column.
Step 3: Subtract the minutes and then the hours.
Example: Subtract 2 hours 45 minutes from 5 hours 30 minutes.
Step 1: Write the time periods: 5 hours 30 minutes - 2 hours 45 minutes
Step 2: Borrow 1 hour: 4 hours 90 minutes
Step 3: Subtract: 2 hours 45 minutes
Answer: 2 hours 45 minutes
Method 2: Conversion Method
Convert the entire time into minutes, perform the subtraction, and then convert back to hours and minutes.
Example: Subtract 1 hour 50 minutes from 3 hours 10 minutes.
Solution: Convert to minutes: 3 hours 10 minutes = 190 minutes
1 hour 50 minutes = 110 minutes
Subtract: 190 minutes - 110 minutes = 80 minutes
Convert back: 1 hour 20 minutes
Therefore, the difference is 1 hour 20 minutes.
Subtraction of time has characteristic properties, as listed below:
Here are some useful tips and tricks for subtracting hours and minutes efficiently:
Tip 1: Always check if borrowing is needed before subtracting minutes.
Tip 2: Use the conversion method for complex calculations, as it simplifies the subtraction process.
Tip 3: Practice mental math with smaller time periods to improve speed and accuracy.
Students often forget to borrow 1 hour when the minuend's minutes are less than the subtrahend's. Always ensure borrowing is done when necessary.
Using the standard method: 4 hours 30 minutes - 1 hour 50 minutes Borrow 1 hour: 3 hours 90 minutes Subtract: 2 hours 40 minutes
Subtract 2 hours 25 minutes from 6 hours
3 hours 35 minutes
Using the conversion method: 6 hours = 360 minutes 2 hours 25 minutes = 145 minutes Subtract: 360 minutes - 145 minutes = 215 minutes Convert back: 3 hours 35 minutes
Subtract 3 hours 15 minutes from 7 hours 5 minutes
3 hours 50 minutes
7 hours 5 minutes - 3 hours 15 minutes Borrow 1 hour: 6 hours 65 minutes Subtract: 3 hours 50 minutes
Subtract 45 minutes from 2 hours
1 hour 15 minutes
Convert to minutes: 2 hours = 120 minutes Subtract: 120 minutes - 45 minutes = 75 minutes Convert back: 1 hour 15 minutes
Subtract 1 hour 40 minutes from 5 hours 20 minutes
3 hours 40 minutes
Subtraction of time can be tricky, leading to common mistakes. Being aware of these errors can help avoid them.
Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.
: She loves to read number jokes and games.