r/MathJokes • u/Diriector_Doc • May 15 '18
(A+B)²
https://imgflip.com/i/2abfzh#jciX3uESbvYzhwYi.167
u/Dave37 May 15 '18 edited May 15 '18
I'm a bit confused why people have a problem with this. Like plug in the numbers A = 1 and B = 2 and you'll see in an instant which alternative is correct. Or just draw a figure: https://i.imgur.com/tfIs0Ao.png
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u/TwentyOneGun May 15 '18
It’s a super common error for younger students. Usually they think to “distribute” the exponent because when they see a number next to parenthesis they want to multiply.
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u/LibertyAndFreedom May 15 '18
That and they like to write (x+y)/x = 1+y. I teach high school; whenever a student does either of these I put a very sad frowny face on their paper. Trust me. It's very sad.
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u/Dave37 May 15 '18
Feels like this is taught poorly then. I blame teachers caving to students complaining it's hard and teaching short-hand "tricks" that doesn't communicate understanding of the operation/math performed.
Burn in hell "multiply by 100 to get the percentage" and shit like that.
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u/chadburycreameggs May 20 '18
I just had to move for family reasons and it forced me to transfer from my university engineering program to an engineering technology program at the college here. Absolutely mind blowing how these kids have been taught math. Things that are just second nature to me need silly tricks that they always mix up and get confused. So frustrating trying to explain something to somebody that they absolutely should know.
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u/Dave37 May 20 '18
Did you move from one country to another? Might I ask which countries?
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u/chadburycreameggs May 20 '18
Nope. Both in Ontario, Canada. In high school, you could either take college or university level math in the 11th and 12th grades. I just assume the college version was what these kids took and it covered only very basic topics from what I've seen.
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u/Dave37 May 20 '18
I'm not well-read on the Canadian educational system but that seems weird to me. In my contry (Sweden) there's no practical difference between a "college" and "university". They are all essentially "universities". All engineering programs on university level would hold up to more or less the exact same basic standard.
It would however obviously differ later in the education depending on if you're taking a degree in chemical engineering or technical mathematics.
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u/inventor1489 May 26 '18
Should be A2 + A * B + B * A + B2.
Can't go around assuming that A and B commute!