In The Range; Rounding - Texas Instruments TI-15 Teachers Manual

In the Range

Overview
Students will interpret the rounding involved in
measuring to identify the possible range of a given
measurement.
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).
1356.5
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.)
© 2000 T I
EXAS NSTRUMENTS
1357 1357.5
I
NCORPORATED
Grades 3 - 6
Math Concepts
• rounding whole
numbers

• rounding

decimals
• measurement
with metric
units (length,
mass, capacity)
³
To fix the display at 2
decimal places, press
Š ™ ®.
³ Have students discuss
how the display of
matches their rounding
of the measurement to
136 cm.
TI-15: A Guide for Teachers
Materials
• TI-15
• pencil
• meter sticks
or metric
measuring
tapes
• student
activity (p.27)
1.36
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