# 4th Grade Math: Help with Elapsed Time

In 4th grade, students learn to solve word problems involving units of measurement, including elapsed time. For an explanation of this concept, as well as some sample problems, read on!

## Math Problems with Elapsed Time

Elapsed time is the amount of time that passes between one point of time and another. Just like you can measure the distance between two points in inches or meters, you can measure the time between two points in seconds, minutes or hours.

### Solving Elapsed Time Problems

The most basic problems will ask you to find the time between two points using addition. For instance, you might get a problem like this one:

Carrie left school at 3:15 p.m., and she returned home one hour and 20 minutes later. What time did she get home?

To solve this problem, begin by adding one hour to the start time. One hour after 3:15 p.m. is 4:15 p.m., so Carrie got home 20 minutes after 4:15. To get your final answer, just add 15 minutes and 20 minutes to get 35 minutes (15 + 20 = 35). Carrie arrived home at 4:35 p.m.

#### Subtraction

You may also solve problems that ask you to find the difference between two times, like this one:

Samantha started her homework at 5:15 p.m. and finished it at 8:05 p.m. If she worked the entire time, how much time did she spend on her homework?

To solve a problem like this, you'll need to figure out how many hours and minutes passed between these two times. One way to solve this problem is by working backwards. If the answer was three hours, then Samantha would have finished working at 8:15 p.m. Instead, she finished working ten minutes before 8:15, which means the answer is ten minutes less than three hours, or two hours and 50 minutes.

#### Multiplication and Division

You may also solve elapsed time problems involving multiplication or division. Some problems will give you the amount of time a particular task takes, and then ask you to figure out how long it would take you to perform the task a certain number of times.

For example, if it takes you one minute and five seconds to do 20 pushups, how long would it take you to do 40 pushups? The answer would be 1:05 x 2, but you can't multiply time the same way you can multiply whole numbers. Instead, multiply the number of minutes by two (1 x 2 = 2) and add that to the number of seconds multiplied by two (5 x 2 = 10). Then put them back together to get your answer, two minutes and ten seconds.

You may also perform the reverse operation. Imagine that you knew you could do 40 pushups in two minutes and ten seconds, and you were asked how many pushups you could do in one minute and five seconds at the same rate. You would divide two minutes and ten seconds each by two to get your answer (one minute and five seconds).

Did you find this useful? If so, please let others know!

## Other Articles You May Be Interested In

• Elementary Math Help: 3rd and 4th Grade

If you have a third or fourth grade student who is having problems with math, you can help them out at home! This article can show parents how to teach their 3rd and 4th grade students the mathematics skill they need to excel.

• MIND Games Lead to Math Gains

Imagine a math teaching tool so effective that it need only be employed twice per week for less than an hour to result in huge proficiency gains. Impossible, you say? Not so...and MIND Research Institute has the virtual penguin to prove it.

## We Found 7 Tutors You Might Be Interested In

### Huntington Learning

• What Huntington Learning offers:
• Online and in-center tutoring
• One on one tutoring
• Every Huntington tutor is certified and trained extensively on the most effective teaching methods
In-Center and Online

### K12

• What K12 offers:
• Online tutoring
• Has a strong and effective partnership with public and private schools
• AdvancED-accredited corporation meeting the highest standards of educational management
Online Only

### Kaplan Kids

• What Kaplan Kids offers:
• Online tutoring
• Customized learning plans
• Real-Time Progress Reports track your child's progress
Online Only

### Kumon

• What Kumon offers:
• In-center tutoring
• Individualized programs for your child
• Helps your child develop the skills and study habits needed to improve their academic performance
In-Center and Online

### Sylvan Learning

• What Sylvan Learning offers:
• Online and in-center tutoring
• Sylvan tutors are certified teachers who provide personalized instruction
• Regular assessment and progress reports
In-Home, In-Center and Online

### Tutor Doctor

• What Tutor Doctor offers:
• In-Home tutoring
• One on one attention by the tutor
• Develops personlized programs by working with your child's existing homework
In-Home Only

### TutorVista

• What TutorVista offers:
• Online tutoring
• Student works one-on-one with a professional tutor
• Using the virtual whiteboard workspace to share problems, solutions and explanations
Online Only