Solving Elapsed Time

1
Solving Elapsed Time

• 4th Grade
• Ms. Salley

2
Elapsed Time, What is it?

• Elapsed time is the amount of time that passes
  between a starting and an ending time.

to
Home
School
3
Strategies

• Guess and Check
• Draw a picture
• Work backwards
• Create a Chart
• Look for a pattern

4
Guess and Check

• It is 1025 p.m. What time will it be in two and
  one half hours?
• Use what you know about addition.

• .

5
HINT

• Remember, after the clock
• strikes twelve, the time switches
• either from a.m. (morning) to p.m.
• (afternoon) or vice versa

6
Draw a Picture

• Use the faces of clocks to solve your problems.

7
Think It Through

• You can solve elapsed time problems more than one
  way.
• Pamelas Way
• 2 hours added to 1025 p.m. makes the time of
  1225 a.m.
• I remembered that once I passed the twelve,
  the time of day changed from night to morning.

8
Think It Through (continued)

• I know that one half hour is 30 minutes. If I use
  five of those
• 30 minutes, it will be 1230 a.m. . But, I
  have 25 more minutes
• to add. I count by fives up the left side of
  the clock until I get to
• 25. This takes me to the 11 on the face of the
  clock. I now have
• 5 minutes before 100 a.m. or 1255 a.m. ?

9
Another Way

• 1025 p.m. plus 30 minutes takes us to
• 1055 p.m. If one hour is added to that,
• we get 1155 p.m. ( We havent passed the
• twelve yet.) Then we add the last hour and
• we get 1255, but is it a.m. or p.m.?
• It is a.m. because we passed the twelve
• p.m., so it is morning!

10
You Try It!

• Find the elapsed time from the start of your
  school day to its end. Ask a partner to explain
  to each other how they found their own elapsed
  time. Be ready to explain your thinking! Have FUN!