Wednesday, January 21, 2009

That Pesky Calculator Percent Key: Flawed Logic

A hand-held calculator is quite handy at stores. I’m really nosey about issues such as how much money I need to hand over.

The percent key on a calculator has always been a mystery to me, but I’ve finally figured it out. It would be embarrassing if I cared to feel that way, but I don’t.

This is my calculator—it saves brain strain. I bought it at Office Max as it’s cute and doesn’t bore me.

Basically, the percentage sign is symbolized by a top number (indicated here by “0”) which is divided/multiplied and otherwise mysteriously manipulated (herein represented as “/”) by a bottom number as symbolized with the second “0”.

I want to buy 5/16 of a yard of Amy Butler’s fabric which is on sale for $9/yard. I’m curious what percentage of yardage I’m purchasing because I want to play with the percent sign.

  • Push the number 5 on the calculator
  • Select the “/” button (my calculator uses a divide symbol instead which means the same thing)

  • Now select 1 and 6
  • Hit the % key

I’m buying 31.25% of 1 yard of fabric. I’ll leave this number on my calculator.

What will the piece of fabric actually cost?

  • Push “X” (for multiplying)
  • Then hit 9 (the fabric price per yard)
  • Hit the % key
It will cost $2.81 (rounded off) before sales tax is added. Again, I’ll leave this number on my calculator.

Now I’ll figure the sales tax choosing an arbitrary number, say 8.5% (because I never remember Arizona’s state tax figure)

  • Push “X” (for multiplying)
  • Push 8.5 (again, the decimal is important)
  • Hit the % key
The sales tax is $0.24 (rounded off). Once again, I’ll leave this number on my calculator.

  • Now push “+” (for adding)
  • Then hit 2.81
Although I’m disappointed I don’t get to use the percent key again, calculator magic tells me the total bill is $3.05.

My husband doesn’t think much of my computations, asserting my logic is flawed. “The percent sign is unnecessary,” he proclaims and illustrates a different way. I immediately protest because his solution doesn’t use my precious percent sign.

Then he whips out another formula he declares is even easier. Just looking at it makes me feel sea-sick and there’s still no percent sign in sight.

“That’s not the point,” I inform him. “The point is learning how to use the blasted PERCENT sign. As such, you flunk.”

Now he’s laughing and making jokes about June Logic. That’s okay; I don’t even need the calculator to figure out that 50% of dinner will not be served tonight. Now that’s logic.


Kristie said...

Ha! That'll learn him. :oD

Anonymous said...

Oh June, this is so over my head :-) I can add, subtract, multiply and do simple division. Anything else is greek to me. I LOVE your calculator -- how pretty! said...

I'm lost... Artists and numbers don't mix well!

kim said...

I always prefer when people who are genius' "speak blonde". Yes, I am blonde. And I am pretty smart. But sometimes, things need to be explained in a different way....

Anonymous said...

That was hilarious, especially the last calculation on dinner!

Thimbleanna said...

Hahaha June -- you're hysterical. I LOVE your logic -- it works in my house too LOL!

Pat @ Mille Fiori Favoriti said...

Any kind of math is a foreign language that I don't speak!
I'm beginning to wonder what it is I'm good at as I'm always seem to be telling everyone what I can't do!

CMMC97 said...

My father and husband ridicule me because I tend to measure in 'men.' Guys are about 6ft tall, right? So a yard is half a man, I need a man and a half for curtains for my windows, etc.

Storybook Woods said...

Math is one of those things that men and women do very different xoxoxox Clarice

Anonymous said...

Thanks for the % tutorial! If you just want the total price, it is actually easier to multiply the item total X itself + sales tax, as your husband did - ex, 9.50 x 1.085 = total cost including tax. A parent volunteer once showed us this during a school book fair & it made it much easier, as long as you don't need the amount of sales tax separately.
Whew! Too much math!~ Better get back to knitting my bandage since I so far have only knit 1/48! Or I could just go play with my pocket calculator.
Jane - Jacksonville