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Canyonlands National Park, Utah
Kimi & Shaun - On Top of the World!

Saturday, June 5, 2010

More on Algebra

There have been a few posts recently about algebra and its relevance in the real world - in particular on the Nightline segment a few days back ( The question seems to be "what if my kids don't learn algebra?" So, I thought, why do we need algebra, and what would we do if we didn't learn it in school? Here are a few examples of algebra in real life:

"How many pies of pizza should we order for dinner tonight?"

x = (n*m)/p

x=number of pies to buy for dinner
n=number of people eating pizza
m=number of slices the average person will eat
p=number of slices of pizza per pie

(or go to "" which I found via Google)

"How long will it take us to drive to our vacation spot?"


d=number of days of driving to get there
m=miles from here to there
n=average number of miles driven each day

(or use MapQuest or Google Maps)

"How much mulch should I buy for the garden?"


m=amount of mulch in cubic feed
l=length of garden in feet
w=width of garden in feet
d=depth of mulch in feet

(or go to "" which I found via Google)

"They sell mulch by the cubic yard. How many cubic yard do I need?"


y=number of cubic yards
f=number of cubic feet

(or go to "" which I found via Google)

I guess I have 2 points:

1. We use algebra regularly without necessarily knowing we're using algebra. I have a problem, I need to solve it, I work on it. Do you think people can learn to solve these kind of real world problems if they don't study algebra as a formal subject? Or, if they didn't study algebra at 12 or 13 years old, can they learn it at 20 or 25 years old?

2. If I don't know algebra, and I need the answer to a question that can be solved with an algebraic equation, I can often just look it up on the Internet. This method is used by my co-workers to solve many technical questions - in fact, it's one of the first things we do when we have a hard question to answer ("Google it....").

So, are we teaching our kids what they need to thrive in the real world when they are adults? Or teaching them what we thought we needed to know to survive in the real world that existed when we were kids?


  1. Love it! Will share with TJ right away! :-D

  2. This is great. I do however, think that a lot of this can be figured out by adding, subtracting, multiplying and dividing, too. I mean, do we really have to do all of this "algebraically"? I'm thinking probably not. :-)

  3. Joni, Algebra IS adding, subtracting, multiplying, and dividing. I would bet money that what YOU are thinking of in those terms IS actually Algrebra, you just aren't assigning variables.

    And, as to the original post...LOVED IT! Part of my unscholling process is, IF a student would ask "And when will I ever need this in real life?" and I cannot answer them, drop it.

    Also, wouldn't the cubic yards question be y=f/27 ?

  4. RebelAngel - Typo! Of course it's f/27. So much for my degree from the School of Math at RPI! (We bought mulch recently, and I went thru all this.)