Mystified by "And"

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#1

<PLEASE USE THE FOLLOWING TEMPLATE TO HELP YOU CREATE A GREAT POST!>

https://www.codecademy.com/courses/learn-python/lessons/conditionals--control-flow/exercises/and?action=lesson_resume

<The hint says “Be careful with bool_four—there’s a big difference between -1 ** 2 and (-1) ** 2! This is meant to be tricky.” Perhaps it has been too many years since eighth grade… how in the world is “(-1) ** 2” any different from “-1 ** 2”? The problem is: “-(1 ** 2) < 2 ** 0 and 10 % 10 <= 20 - 10 * 2”. As far as I can tell, the first part (before “and”) is “-1 < 2” and the part after “and” is “1 <= 20 - 20”. I cannot figure out how I could possibly be getting anything but “True and False” for the answer.>

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bool_four = True and False

<do not remove the three backticks above>
#2

math has order of operations, do you remember this from eight grade? (multiplying comes before sum)

so ** comes before -, so -1**2 is 1**2 which is 1, so then we get -1

while (-1)**2 can also be written as -1 * -1 which is 1

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#4

Oooohhhhhhhhh, of course! Thank you. I was beating my head against the wall. I was thinking they had screwed up the order of operations by failing to recognize that 20-10*2 is zero, not twenty. I was confident they wouldn’t screw up the order of operations, though, so I knew the problem must have been me.

#5

Okay, so you understand everything now? Any further assistance needed?

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#6

That first question pertaining to -1 didn’t affect the outcome of my code. The real reason I posted the question was to address the second part. The second part appears to be “1 <= 0” which should be false.

#7

i see your confusion, which is here:

10 % 10

this is the modulo operator, not the division operator. 10 / 10 is 1, that is true enough. But what is 10 % 10? Remember what the modulo operator does?

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#9

Okay, lets do an example for 16 % 5

We are at a party, with a total of 5 people. And we have a pie, and we cut the pie in 16 pieces (or we have 16 candy-bars, whatever, doesn’t matter), and i am going to everyone as much pieces as pie of possible,

can i give everyone one piece of pie? yes
can i give everyone two pieces of pie? yes
can i give everyone three pieces of pie? yes
can i give everyone four pieces of pie? no

so i can give a maximum of 3 pieces of pie to every person, if i do, how many pieces do i have left? One piece, so the remainder is 1

Now, apply this same logic for your problem.

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#10

Thank you! I appreciate all your help! No further assistance needed.

#11

you’re welcome. Now you see what the outcome of the math is, you also understand where the true is coming from.

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#12

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