Eli5 why is a number divided by zero undefined?

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Example I have a pizza I cut it into zero pieces shouldnt it be still one whole pizza?
Since I didn’t cut it so it’s still whole

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Anonymous 0 Comments

If you cut a pizza into 2 pieces, how many of those pieces would you need to put together to make a whole pizza? Two, right?

If you cut a pizza into 3 pieces, how many of those pieces would you need to put together to make a whole pizza? Three right?

If you cut a pizza into “0” pieces, how many of those pieces would you need to put together to make a whole pizza? Er…

Division by zero is undefined because it’s meaningless and people get confused when you “cut something into 0 pieces” (which is not the same as “don’t cut the pizza”, as the trap you fell into… that’s actually just “cutting it into 1 piece”, i.e. leaving it intact).

All you have to do is look at it the other way around.

12 / 4. How many 4’s do you need to add together to make 12? 3 of them. 4 + 4 + 4

12 / 2. How many 2’s do you need to add together to make 12? 6 of them. 2 + 2 + 2 + 2 + 2 + 2

12 / 0. How many 0’s do you need to add together to make 12?

Try it. 0. +0. +0. +0. Still adding up to zero. Should we keep going? +0 +0 +0 ? When will we hit 12? Never.

And even if you consider the SINGLE exception:

0 / 0. How many 0’s do you need to add together to make 0? Well, one. One zero added together will total zero. But so will two zeroes. And three zeroes. In fact any number of zeroes, added together, will total 0.

So the “answer” is either: No amount of 0’s will add up to the target number. Or EVERY amount of zeroes will add up to the target number.

Hence, division by zero is just unnecessarily difficult, complicated, fairly useless, and doesn’t help, and thus is generally undefined.

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