Friends,
Since all kinds of stories came up, here is my own experience at a
supermarket check-out in Clumbus, Ohio some three years ago, while we were
on sabbatical.
We bought all kinds of stuff, and on our way out saw a big sign proclaiming
that they had a "5 percent grand parents discount" on all purchases that
evening. Our bill came to whatever it was and the young man at the counter
(a high school student) who was very efficient and nice said: "$128.-,
please". I said: "we are grandparents", which made him obviously nervous
and he asked his neighbor cashier: "how do I do this?". I said to him:
"simply deduct 6 dollars and fourty cents, and you will get $121.60" to
which he answered: "how do you know?" I carefully explained to him that one
simple way to know how to get the 5% is to take a tenth and than half of
it. The young man had a totally glazed look on his face, and called the
supervisor (this one was already a college student) who started hammering
on the keys of his calculator and finally got there...
Where is simple arithmetic gone?
Prof. Uri Ganiel
Head, Department of Science Teaching
The Weizmann Institute of Science
Rehovot 76100, ISRAEL