MATH213
posted by Rebecca on .
6. Explain how you would respond to the following:
a. A student claims that 9443/9444 and 9444/ 9445 are equal because both display 0.9998941 on his scientific calculator when the divisions are performed.
b. Another student claims that the fractions are not equal and wants to know if there is any way the same calculator can determine which is greater.

My calculator goes out one more decimal place to show the difference. I do not know any way your calculator could show it. Sorry.

Calculators usually store more numbers internally than on the screen.
Since you get 0.9998941, ask the student to subtract 1 from ANS. (If you don't have an ANS button, you can press the subtraction sign after pressing equal sign for the same effect as pressing "ANS" and "" )
Then times it by 10 using the same method to move all the digits to the left. Then continue this process until you got the precision you wanted.
So for 9444/ 9445, the buttons I would press would be:
9444
/
9445
=

.9
=
*
10
=
This will move all the digits one spot to the left