Elapsed Time

Grade 3 · measurement · 100 practice problems · read aloud

🔊 Listen to this explanation

⏱️ What is Elapsed Time?

Elapsed time is the amount of time that passes from the start of an activity to the end. We use it all the time! For example, to figure out how long your soccer practice lasts or how much time you have until dinner.

How to Find Elapsed Time: Step-by-Step

  1. Identify Start and End Times: Write down when the activity began and when it finished.
  2. Count the Hours: Count forward from the start time to the end time, one hour at a time.
  3. Count the Minutes: After counting the hours, count any extra minutes.
  4. Put It Together: Combine the hours and minutes to find the total elapsed time.

Visual Examples

Example 1: Movie starts at 4:15 PM and ends at 6:15 PM. How long is the movie?

  • Start: 4:15 PM
  • End: 6:15 PM
  • From 4:15 to 5:15 is 1 hour.
  • From 5:15 to 6:15 is another 1 hour.
  • Total Elapsed Time: 2 hours 🎬

Example 2: You start reading at 2:30 PM and finish at 3:45 PM. How long did you read?

  • Start: 2:30 PM
  • End: 3:45 PM
  • From 2:30 to 3:30 is 1 hour.
  • From 3:30 to 3:45 is 15 minutes.
  • Total Elapsed Time: 1 hour and 15 minutes 📚

⚠️ Common Mistakes to Avoid

  • Forgetting to count hours AND minutes: Always check both!
  • Counting by 1s instead of 60s: Remember, 60 minutes make 1 hour, not 100.
  • Confusing A.M. and P.M.: A morning time (A.M.) is different from an afternoon/evening time (P.M.).

💡 Tips & Tricks

  • Use a number line: Draw a timeline and hop forward to count the time.
  • Break it into chunks: Count to the next hour first, then add the rest.
  • Think of a clock: Imagine the hands moving on an analog clock to help you count.

How to Practice

Become an elapsed time expert! Try these activities:

  • Time how long it takes to do your homework.
  • Ask a family member to give you start and end times for your daily activities.
  • Use online math games that focus on telling time and elapsed time.

Practice problems

6 of the 100, worked through step by step — try them before opening the answer.

1 125 × 4 = ?

Hint: Think about how to multiply a three-digit number by a single digit. You can break it down by place values.

Show the answer

Answer: 500

  1. Understand the problem. We need to multiply 125 by 4.
  2. Break down the multiplication. 125 means 100 + 20 + 5. So, 125 × 4 = (100 + 20 + 5) × 4.
  3. Multiply each part separately. First, 100 × 4 = 400. Second, 20 × 4 = 80. Third, 5 × 4 = 20.
  4. Add the results together. 400 + 80 = 480. 480 + 20 = 500.
  5. Conclusion. 125 × 4 = 500.

2 324 ÷ 6 = ?

Hint: Think about how many times the divisor fits into the dividend using basic division facts.

Show the answer

Answer: 54

  1. Set up the division. We want to divide 324 into groups of 6.
  2. Start with the first digit of 324, which is 3. 3 ÷ 6 = 0 with a remainder of 3. So we write 0 above the 3, but since it's the first digit and it's less than 6, we actually consider the first two digits together.
  3. Take the first two digits: 32. 32 ÷ 6 = ? 6 × 5 = 30, which is less than 32. 6 × 6 = 36, which is too big. So we use 5. Write 5 above the 2 in 32.
  4. Multiply 5 × 6 = 30. Subtract 30 from 32: 32 − 30 = 2.
  5. Bring down the next digit (4) from 324. Now we have 24.
  6. Divide 24 by 6. 24 ÷ 6 = 4. Write 4 above the 4 in 324.
  7. Multiply 4 × 6 = 24. Subtract: 24 − 24 = 0. There is no remainder.
  8. The quotient is 54. So, 324 ÷ 6 = 54. Final check: 6 × 54 = 324, which matches the original number. Answer: 54

Let's solve 324 ÷ 6 step by step.

3 125 ÷ 5 = ?

Hint: Think about how many groups of the second number fit into the first number.

Show the answer

Answer: 25

  1. Understand the problem. We are dividing 125 into 5 equal groups. We want to find how many are in each group.
  2. Start with the largest place value. Look at the first digit of 125, which is 1 (from the hundreds place, so it's 100). Ask: How many groups of 5 can we make from 1? None, because 5 is larger than 1. So we must look at the first two digits: 12 (which is 12 tens, or 120).
  3. Divide 12 by 5. 5 times what number is close to 12? 5 × 2 = 10. This fits, because 10 is less than 12. Write down 2. This 2 is for the tens place, so it represents 20.
  4. Subtract and bring down. 12 - 10 = 2. Now bring down the next digit from 125, which is 5. This makes 25.
  5. Divide 25 by 5. 5 times what number equals 25? 5 × 5 = 25. Write down 5. This 5 is for the ones place.
  6. Combine the results. We wrote down 2 (tens) and then 5 (ones). This gives 25.
  7. Check the answer. Multiply the result by the divisor: 25 × 5 = 125. This matches the original number, so the division is correct. Final Answer: 25

Let's solve 125 ÷ 5 step by step.

4 245 + 178 = ?

Hint: When adding larger numbers, remember to regroup if the sum in any column is 10 or more.

Show the answer

Answer: 423

  1. Write the numbers vertically, aligning the digits by place value (ones, tens, hundreds). 245 + 178 ______
  2. Add the ones column: 5 + 8 = 13. Since 13 is 10 + 3, we write down the 3 in the ones place and carry over the 1 (which is 1 ten) to the tens column. 1 245 + 178 ______ 3
  3. Add the tens column: 4 + 7 = 11, plus the carried-over 1 makes 12. Since 12 tens is 100 + 20, we write down the 2 in the tens place and carry over the 1 (which is 1 hundred) to the hundreds column. 11 245 + 178 ______ 23
  4. Add the hundreds column: 2 + 1 = 3, plus the carried-over 1 makes 4. Write down the 4 in the hundreds place. 11 245 + 178 ______ 423 Final Answer: 423

Let's add 245 and 178 step by step.

5 Start: 9:35 AM, End: 1:15 PM. How long?

Hint: Think about how many hours and minutes pass from the start time to the end time. You can count the hours first, then the minutes.

Show the answer

Answer: 3 hours 40 minutes

  1. From 9:35 AM to 12:35 PM is 3 hours (9:35 to 10:35, 10:35 to 11:35, 11:35 to 12:35).
  2. From 12:35 PM to 1:15 PM is 40 minutes (12:35 to 1:00 is 25 minutes, plus 1:00 to 1:15 is 15 minutes, total 25+15=40 minutes).
  3. Add the hours and minutes: 3 hours + 40 minutes = 3 hours 40 minutes.

The answer is 3 hours 40 minutes.

6 Start: 9:47 AM, End: 2:18 PM. How long?

Hint: Break the time into parts: first go to the next hour, then to the end time. Remember to count carefully how many hours and minutes pass.

Show the answer

Answer: 4 hours 31 minutes

  1. From 9:47 AM to 10:00 AM is 13 minutes (60 - 47 = 13).
  2. From 10:00 AM to 2:00 PM is 4 hours (10 to 11, 11 to 12, 12 to 1, 1 to 2).
  3. From 2:00 PM to 2:18 PM is 18 minutes.
  4. Add the minutes: 13 + 18 = 31 minutes.
  5. Total elapsed time is 4 hours and 31 minutes. Final answer: 4 hours 31 minutes.
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