Sharp EL-531RH, Teachers Manual

Page: 32 / 56

31
Junior high school
Trial and Improvement
• • • • • • • • • • • Using the activity in the classroom • • • • • • • • • • •
This activity may be given to students with little introduction or, with the use of the OHP unit, this
or a similar task may be introduced to the whole class followed by individual work on one or more
of the extension activities. The use of the multi-line playback function will be of practical benefit in
tackling questions involving trial and improvement.
• • • • • • • • • • • • • • • Points for students to discuss • • • • • • • • • • • • • •
It will be necessary to familiarize the students with the FSE and TAB keys in order to understand,
for example, why 4.641
3
and 4.642
3
both have the value 1 00 to the nearest unit. In the context of
similar problems, students will need to consider what degrees of accuracy are appropriate; in the
case of cubic centimeters of ice cream, possibly only to one decimal place.
Further Ideas
• Find the side of a cubical carton whose volume is
1
/2 liter. It may be necessary to remind
students of the equivalence of 500 ml (fluid measure) and 500 cm
3
(solid measure).
• Find the dimensions of a fruit juice carton whose sides are in the proportion 1 : 2 : 3 and
whose capacity is
1
liter.
• Find the Golden Ratio x by trial and improvement of the relation
Guess x (Guess +
1
) =
1
Use the playback function on the calculator to show that
x = 1 / ( 1 + x) and that x = .
All metric paper has the same shape (except golden). If A0 has an area of 1 m
2
and the longer
side is times bigger than the smaller side, find these dimensions. What are the dimensions
of A4? Have the students confirm their calculations by measuring a sheet.
Switch FSE and TAB to normal display for further operation.
Press FSE until FIX, SCI, or ENG are not shown on the display.
DEG