So may anyone please explain to me what's subtract means?

Ryan$

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Hi guys, I don't know why but I find it hard sometimes to visualize a subtraction.
I mean lets assume I have 5 zoos - 4 zoos, how many zoos are left, 1 zoo .. but once the question talks about bits in computing world, then for example 20 bits - 4bits, how many bits left? I sometime get stuck three hours on that simply question .... and I think that's because I don't know what subtract means, as a result I must first understand what's the term subtract mean in order to get used by it and manipulate it by problems/question.

So may anyone please explain to me what's subtract means? dont tell me it means subtract two quantity .. I need something more senseable .. thanks alot
 

Otis

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Subtraction is the inverse operation of addition.

💡
 

Dr.Peterson

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We define a - b as the number c such that a = b + c. For example, 20 - 4 is the number x such that 20 = 4 + x, namely 16.
 

Harry_the_cat

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Line up 5 oranges on your kitchen bench. Take 2 away. Now there are 3 on the bench. You have "subtracted" 2 oranges.
 

Ryan$

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thanks alot
 

Ryan$

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Hi guys, I already know that almost of the helpers here have known of my problem of subtraction so please take that into consideration and I need to understand, so endure me :) !

lets assume that I have 10 electric polls , which they are numbered from 1 to 10 ! , I was on poll number 1 and each time I'm jumping to the other poll. so if I was on poll number one and I jumped three jumps then 1 + 3 (polls) = 4 , so I'm on poll number 4 ! so now lets assume I want to back two steps so if I do 4-2 then I will be between poll number 2 and poll number 3 so actually I will not go to poll number 2, and that's converse the math which 4-2=2 so I must be on poll 2 .. any help?

what I try to say, when I was on poll number 4 and subtracted two polls, then actually smashed two polls and I'm now between the poll number 2 and poll number 3...not actually on the poll number 2 ... so that's converse to math .. any help? I think I'm not understanding the idea ..
 

Ryan$

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what's confusing me about subtraction, if I'm on polls number 4 I smashed "analogy" two polls, then I would be on the space between the poll number 2 and poll number 3 .. so it's converse to math which 4-2=2 which I must be on poll number 2
 

Denis

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Take a pill Ryan :geek:
 

Dr.Peterson

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Why between two poles? (That's the spelling you want, by the way.)

Here's jumping 3 steps, from #1 to #4:
Code:
o-->o-->o-->o   o   o   o   o   o   o  ... 1 + 3 = 4
Here's jumping back 2 steps from #4:
Code:
o   o<--o<--o   o   o   o   o   o   o  ... 4 - 2 = 2
Now you're at #2.

Who or what is smashed?
 

Ryan$

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Why between two poles? (That's the spelling you want, by the way.)

Here's jumping 3 steps, from #1 to #4:
Code:
o-->o-->o-->o   o   o   o   o   o   o  ... 1 + 3 = 4
Here's jumping back 2 steps from #4:
Code:
o   o<--o<--o   o   o   o   o   o   o  ... 4 - 2 = 2
Now you're at #2.

Who or what is smashed?
I mean with "between" like this case:
o o im here o<----o <---o

If you see "im here" means thats im between third and second poll ... Not on #2 poll!!! However i subtract two "back two jumps" and didn't arrive to poll #2..any help?!
 

Dr.Peterson

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Why do you believe you would not be on the pole? You must have some reason for saying this, if you expect us to take you seriously.
 

HallsofIvy

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It's not clear to me why you would think that "20 bits - 4bits" is at all different from "5 zoos - 4 zoos". (Actually, subtracting bits makes a lot more sense to me than subtracting zoos!) Perhaps you are working with a problem where you have to convert from one unit to another: subtract 4 bytes, 7 bits from 9 bytes, 2 bits?

Since 7 bits is larger than 2 bits, "borrow" from the bytes. One byte is 8 bits so "9 bytes, 2 bits" is the same as "8 bytes, 10 bits". Subtracting 4 bytes, 7 bits from 8 bytes, 10 bits is 4 bytes, 3 bits.
 

Otis

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HallsofIvy

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"Pole" or "poll"?
 

Otis

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"Pole" or "poll"?
It's pole, as in 'electric pole' (see post #6).

Dr. Peterson already advised Ryan$ regarding the spelling, but I think Ryan$ is not always willing (or able) to pay attention to replies in their entirety.

😐
 
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