B : Hello there, Terry. How are you doing?
G : Not too well. I’m really having trouble figuring
out this arithmetic assignment. I can add and
subtract pretty well, but without a calculator it’s
difficult for me to multiply and divide. Hey,
Olaf, I heard that you’re excellent in math.
B : My technique is that I try to imagine pictures in
my mind, so the numbers aren’t just figures on a
page, but something I can apply to real life. One
way I do this is to imagine the numbers as if they
were money. For example, if the equation is 753
minus 236, I think about seven dollars and 53
cents minus two dollars and 36 cents. It’s five
dollars and 17 cents, or 517. Easy!
G : Wow, that does seem easier, for adding and
subtracting. But how do you apply this technique
to multiplying and dividing?
B : OK, suppose the equation is 200 times 30. 30 is
three groups of 10. So, first I imagine 10 groups
of people standing in a large field. Next to each
group is a sign with the number 200 on it. At the
front of the field is a huge sign with the number
2,000 on it, because 200 times 10 equals 2,000,
right? But the problem requires 200 times 10
three times, so, I just add two more fields of
people to my picture, with two more signs that
say 2,000. Now I have 2,000 times three. The
answer is 6,000!