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EXAS
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NSTRUMENTS
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TI-15: A Guide for Teachers
24
In the Range
Grades 3 - 6
Overview
Students will interpret the rounding involved in
measuring to identify the possible range of a given
measurement.
Math Concepts
• rounding whole
numbers
• rounding
decimals
• measurement
with metric
units (length,
mass, capacity)
Materials
• TI-15
• pencil
• meter sticks
or metric
measuring
tapes
• student
activity
(p.27)
Introduction
1. Have students measure the length of a table or
desk in the room and record the measurement to
the nearest millimeter, for example, 1357 mm.
Discuss how measurements in millimeters can be
recorded as 1357 mm or as thousandths of
meters, 1.357 m. Note that the measurement was
rounded to 1357 mm because it fell somewhere
between ½ of a millimeter less than 1357 mm
(1356.5 mm) and ½ of a millimeter more than
1357 mm (1357.5 mm).
2.
Have students then use rounding to record the
same measurement to the nearest centimeter
(136 cm or 1.36 m).
3.
Enter the original measurement on the calculator
as 1.357 and fix the display at two decimal
places.
4.
Have students fix the display at one decimal
place. Ask:
What does this number represent?
(The
measurement rounded to the nearest tenth of a
meter, or the measurement rounded to 14
decimeters.)
³
To fix the display at 2
decimal places, press
Š
™
®
.
³
Have students discuss
how the display of
1.36
matches their rounding
of the measurement to
136 cm.
1356.5 1357 1357.5