A. Round each number to the specified place value.

1. 45 980 (thousands)
2. 99 827 (ten thousands)
3. 567 (tens)
4. 73 495 (hundreds)
5. 84 805 (ones)

B. Flash the numbers. Arrange the digits to form four-digit numbers to answer the questions below.

1. The highest number that rounds 4000 is _____________.
2. The highest number that rounds to 9000 is ___________.
3. A number that rounds to 1000 is __________.
4. A number that rounds to 6000 is __________.
5. The lowest number that rounds to 5000 is ___________.

4, 5, 1, 8

Round to the highest place value, then find the sum or difference.

1. 45 980 _________

+ 9 489 _________

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• 87 456 _________

- 23 789 _________

• Does she have a companion?
• How about you, do you also work without being told or when no one is watching?

The ground of Castro Elementary School is planted with mangoes. Lorena and her group mates started to clean the ground at exactly 6:40 a.m. They finished cleaning at around 7:19 a.m. About how many minutes did they spend cleaning the school ground?

• What are the girls doing?
• At what time did they start and finish cleaning?
• What is asked in the problem
• How will you solve the problem?
• What operations will be used to find the answer?

Let the pupils work with a partner to solve the problem.

Answers:

1. The estimated length of time they spend cleaning.
2. 6:40 a.m. ; 7:19 a.m.
3. Subtraction
4. 7:19 – 6:40 = N
5. Solution

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Estimated elapsed time Actual elapsed time

1 hr = 60 mins

7:19 7:20 = 6:80

• 6:40 6:40 - 6:40

0:40 mins

1 hour is 60 mins

7:19 = 7:19 = 6:79

• 6:40 - 6:42

0:37 mins

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f. They cleaned for about 40 minutes.

g. To make computation easier and to check if our answer is reasonable.

Think of 7 hours 20 minutes as 6 hours 80 minutes.

Think of 7 hours 19 minutes as 6 hours 79 minutes.

• Is there a difference between the exact elapsed time and estimated elapsed time?
• Is the estimated time reasonable?
• How did you estimate time in minutes?

Rod jogs everyday around the park. This morning, he started jogging at 6:12 a.m. and ended at 6:48 a.m. About how long did he jogs this morning?

• What is being asked in the problem?
• Will you compute for the exact time that Rod spent in jogging
• What will you do then?
• Estimate the amount of time spent by Rod in jogging.
• How will you do it?

Round the times in minutes.

Study this.

Actual Times Estimated Times

6:48 6:50

- 6:12 - 6:10

0:36 0:40

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Therefore: Rod jogged for about 40 minutes.

Try to round the actual elapsed time. Is your answer reasonable?

Subtract the rounded times.

Work by pairs to find the estimated elapsed time for the following situations.

1. Amado begins his breakfast at 7:08 a.m. and finished eating at 7:39 a.m. About how long did it take him to eat?

What is the solution?

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• Rafael arrived late in his Math class. He entered the class at 9:18 a.m. If the class starts at 9:00 a.m., about how many minute was he late?

Do the same process in solving the problem.

Solution for a.

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7:39 7:40

- 7:08 - 7:10

0:31 0:30

(actual elapsed (estimated elapsed

time) time)

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Amado took about 30 minute to eat his breakfast.

Round 7 hours 39 minutes to 7 hours 40 minutes.

Round 7 hours 8 minutes to 7 hours 10 minutes.

Do you know the term which means the scientific study of matter, energy, force, and motion and the way they relate toe ach other? Find the word by finding the estimated elapsed time of the table below.

During the Physical Fitness Test (1000-m walk/run), five boys recorded their time in table below. Complete the table by filling in the estimated and actual elapsed time.

How do we estimate the elapsed time in minutes?

To estimate the elapsed time, round the minutes in the time ended and time started to tens. Then, find the difference.

Find the estimated and actual elapsed times in each situation below:

1. The Tabilang family arrived in Baluarte at 10:28 in the morning. They left their house at 10:05 a.m.

Estimated elapsed time: _____ Actual elapsed time: _____

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• Lolita started eating her dinner at 6:35 p.m. and finished eating at 7:03 p.m.

Estimated elapsed time: _____ Actual elapsed time: _____

3. Section A of the Grade 4 class of Sudipen Central Elementary School started their tour around Barangay Poblacion at 8:06 a.m. They were back to school at 8:58 a.m.

Estimated elapsed time: _____ Actual elapsed time: _____

4. Lorena and Ian started working on their project in Music after their classes in the afternoon at 5:30 p.m. They finished their project at 6:05 p.m.

Estimated elapsed time: _____ Actual elapsed time: _____

5. Rayman was called to the principal’s office at 3:22 p.m. He came back to his room at 3:45 p.m.

Estimated elapsed time: _____ Actual elapsed time: _____

A. Complete the table by filling in the elapsed time.

B. Solve for the correct answers o the following problems:

1. Rafael arrived home 5:55 in the afternoon. If he left school at 5:28 p.m., about how many minutes did it take him to reach home?
2. Jimmy started encoding his project in Science at 7:05 p.m. and finished at 7:56 p.m. About how long did he encode his project?

Write the elapsed time inside the oblong and the estimated elapsed time in the rectangle.

Solve the following problems:

1. The class began to rearrange the furniture inside the library at 9:35 a.m. They finalized the arrangement at 10:49 a.m. About how long did it take them to arrange the furniture?
2. Lian served as an assistant in the library. He started to work at 6:15 in the morning. He left the library to attend his Math class at 8:50 a.m. About how long did he assist in the library?