Basic Arithmetic : Addition and Subtraction with Time

Study concepts, example questions & explanations for Basic Arithmetic

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Example Questions

Example Question #1 : Addition And Subtraction With Time

Jimmy started taking his math test at 11:03AM, and he finished at 12:29PM. How many minutes did it take Jimmy to finish the test?

Possible Answers:

Correct answer:

Explanation:

First, we need to find how long it took Jimmy to finish the test.

Subtract the hours, then subtract the minutes.

Now, the question asks how many MINUTES it takes Jimmy to finish the test. Convert the hour into minutes.

Example Question #2 : Addition And Subtraction With Time

Pete worked on his homework, and it took him  hour and  minutes to finish. If he started his homework at , what time did he finish his homework?

Possible Answers:

Correct answer:

Explanation:

To add time, you add the hours together, then you add the minutes together.

Because there are only 60 minutes in an hour, you cannot have a time whose minute value is greater than 60. In this case, subtract 60 minutes and add 1 more to the hour.

Example Question #3 : Addition And Subtraction With Time

If you lie down to take a nap at , and you nap for  minutes, what time will it be when you wake up?

Possible Answers:

Correct answer:

Explanation:

First, we need to convert  minutes into the combination of hours and minutes. One hour is equal to  minutes therefore, we can rewrite  minutes as the following:

and because

Now we need to add  to

.

Thus you wake up from your nap at .

Example Question #4 : Addition And Subtraction With Time

Please choose the best answer for the question below. 

If Andrew leaves his house at pm and it takes him exactly two hours and fourteen minutes to get to his office, and then another eight minutes to get to his desk, at what time will he be at his desk?

Possible Answers:

pm

pm

pm

pm

pm

Correct answer:

pm

Explanation:

The first step in this process is to add two hours and fourteen minutes to pm.  Simply add them together, hours first, and then minutes:

Hours 

Minutes: 

So we know now that Andrew made it to his office at pm.  Add your final eight minutes to complete the problem:

.

The hour has not changed, so we know that Andrew arrived at his desk at pm.  

Example Question #5 : Addition And Subtraction With Time

Melissa started practicing piano at 3:34PM. She practiced until 5:17PM. How long did she practice for?

Possible Answers:

2 hours and 43 minutes

2 hours and 17 minutes

1 hour and 17 minutes

1 hour and 43 minutes

Correct answer:

1 hour and 43 minutes

Explanation:

To subtract time, subtract the minutes then subtract the hours.

Since we can't have negative minutes, add 60 to the minutes and subtract 1 from the hours (60 minutes = 1 hour).

Example Question #6 : Addition And Subtraction With Time

Nate started his math, history, English, and French homework at . It took him  minutes to finish his math homework,  minutes to finish his history homework,  minutes to finish his English homework, and  minutes to finish his French homework. What time did Nate stop doing homework?

Possible Answers:

Correct answer:

Explanation:

First, start by adding up the total amount of time Nate spent on doing his homework.

Now, subtract  minutes until the number of minutes is less than  to figure out how many hours and minutes it took him to do his homework.

 

Because we subtracted  twice, we know that he has done  hours and  minutes worth of homework.

To figure out when he finished doing his homework, add the hours together then add the minutes together.

So then he finished at 

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