Elapsed Time . . . Why so much confusion?
Slide 1
Rm. 103-105
2:45-4:00
4/19/2013
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Elapsed Time . . .
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• What is it?
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• Why is it so difficult
for students to grasp?
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• Why do teachers become
frustrated while teaching it?
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Slide 4
The Mysterious Math Malady
“When we ask teachers in graduate courses in
primary mathematics what is especially hard
for them to teach, the answer they often give
is elapsed time. If we ask what makes elapsed
time so hard to teach, the teachers become
unsure. We made a search of the research
literature to find out what is known about this
difficulty but found nothing.”
Constance Kamii, University of Alabama
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Slide 6
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How would you define
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TIME
?
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Elapsed Time . . . Why so much confusion?
Slide 7
If TIME is _____________ ,
then what is ELAPSED TIME?
Rm. 103-105
2:45-4:00
4/19/2013
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Slide 9
Students equate
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=
TIME
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• It is critical that we, as teachers, work to clarify
this misconception in order for students to
conceptually understand the concept of TIME.
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Slide 10
Exact time vs. Elapsed time
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Elapsed Time . . . Why so much confusion?
Slide 12
Rm. 103-105
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6
6
7 :115
- 5 : 45
1 : 70
60
6
7 hrs. 15 min.
- 5 hrs. 45 min.
1 hr. 15 min.
4/19/2013
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When all else fails,
try the algorithm!
7 : 15
- 5 : 45
2 : 30
2:45-4:00
60+15=75
7 hrs. 15 min.
- 5 hrs. 45 min.
1 hr. 30 min.
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Slide 14
Reform Method
. . . what on earth is this?
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Slide 16
This can be a number line. However, since we are
talking about TIME today, what else might it be called?
PROBLEM: Maria started reading at 8:30. She finished at
10:05. How long did it take her to finish her book?
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Where would start time be recorded? Stop time? Why?
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Elapsed Time . . . Why so much confusion?
Slide 19
Rm. 103-105
Use your Time Pieces™ to “count on”
from start time to stop time.
PROBLEM: Maria started reading at 8:30.
She finished at 10:05. How long did it
take her to finish her book?
2:45-4:00
4/19/2013
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8:30
10:05
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Slide 20
Place each piece on your time line and
record the time under it as you “count
up” to the stop time.
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8:30
9:30
10:00
10:05
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Slide 21
Where’s my answer?
Jabar started reading at
8:30. He finished at 10:05.
How long did it take him
to finish his book?
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1 hr
60 min
+
5 min + 30 min=
35 min
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Elapsed Time . . . Why so much confusion?
Slide 24
Choosing manipulatives
Be careful to choose manipulatives that do not
“cripple” students. A “good” manipulative :
Rule #1- Allows for multiple strategies/solutions.
Rule #2- Connects to mathematical concepts that
have already been introduced (i.e. fractions).
Rule #3- Is able to be represented pictorially
(drawn) after familiarity or when the manipulative is not available.
Rm. 103-105
2:45-4:00
4/19/2013
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Slide 25
Now HEAR this!
Prior to State Assessments . . .
It is my responsibility (as the teacher) to make
sure that my students have drawn every single
math manipulative in my classroom.
How can I do THAT?
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Slide 30
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Barbara Spotts
[email protected]
www.JohnnysKey.com
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Cell: 570-809-2840
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“The journey IS the destination.”
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