
Section 6: Functions84


Notice that the calculated answer writes over the percent rate in the
Xregister, and the base number is preserved in the Yregister.


Since the total tomato weight is still in the Yregister and the weight of
the water in the tomato is in the Xregister, the weight of the remainder
can be obtained by simply subtracting:




Percent of Change


The %CH (percent of change) function is a
twonumber function that calculates the percent increase or decrease from
a number in the Yregister to the number in the Xregister. To find the
precent of change:



1.

Key in the base number (usually, the number that happens first in time).



2.

Press ENTER .



3.

Key in the second number.



3.

Execute the %CH function form the
display. Percent of change is calculated as %CH = [(x – y) 100]
÷ y. (When y = 0 a value of
9.999999999 × 10^{99} is placed in the Xregister and the
calculator displays OUT OF RANGE.)



Example: Tomato grower Flem Snopes has found
that he can decrease the amount of water in the
tomatoes he is growing. His typical tomato weighs
about 500 grams. He has found that only 430 grams
of the total weight is water, compared to 470 grams of
water in the tomato from the previous example. What
is the percent of change of water amount between the
average tomato and Snopes’ tomato?




