Math People... Why when you do 10/2 it doesn't equal 4.999?

Question

My teacher wants to know why when you do 10/2 the regular way u get 5 but when you do it this way you get 4.999. Okay when you write 10/2 on some paper then u say 2*5 equal 10 but instead since its even you subtract on and write 4 instead. u continue this on and you get 4.99. Is this a true answer or no? Please help

Answer 1

your calculator is automatically programed to believe that 10/2 = 5.

hopefully this example helps you:

1/3 = .333333333333 with the 3 going on forever

2/3 = .66666666666 with the 6 going on forever (calculators will give you a 7 at the end to round off the number)

3/3 = 1, but is really supposed to be .999999999999999999 but because the decimal infinitely repeats itself, it is rounded up to 1

also, .33333 x 2 = .66666 (1/3 x 2 = 2/3), and .33333 x 3 = .99999 (which is 3/3)

do not divide the fractions!!!!!!!

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4.9999999999999999 goes on forever with the repeating 9

4.99999 x 2 = 10 when it is rounded up, because .00000000000000000002 (with forever in the amount of zero's) is such a small number mathematicians don't care for it.  

Answer 2

this is very unclear.

I cannot understand what is it that you want.

Answer 3

Its Simple, your calculator is made in China

Answer 4

4.999999999*2 does not equal 10.  it equals 9.999999998.  

is this what calculators have done to our society?  

Answer 5

4.99 = 4 99/100

5 =  4 100/100

they are clearly not the same

Answer 6

Ten divided by two is five. There is no further debate.

Answer 7

it is just 5*2= 5+5=10

Answer 8

When you try to solve a problem using an infinite series, you can never completely resolve the actual answer unless you can go to infinity. So you have to go to completeness by some other schemes, such as rounding up or down, or consider in math terms that infinity can be achieved. Wait until you take calculas, and you will see this in detail.

Answer 9

There's a debate that says that .99999(repeating) is equal to 1

there are many proofs for it

I'm not quite sure if I answered the question, but it is stated in such a way that I can't quite understand it. I got it until you wrote "subtract on and write 4 instead"

Answer 10

It is only rounded up to l0 - it does not equal 10..  And why would you want 2 whole numbers to equal anything but a whole number?

Answer 11

"since it's even you subtract on"  WHAT DOES 'on' MEAN? ... "one?"

or do you mean 'continue subtracting?' ('subtract on and on and on')

and why would you "subtract one(e)?"

what's that all about?

Let's put it another way: if you have 10 pennies and you divide them into 2 equal piles, you will ALWAYS have 5 (count 'em, FIVE) pennies in each pile. Not 4.999 pennies in one pile and 5.1 pennies in another pile. Why? because 10 is a WHOLE number. and 2 is a whole number. dividing a whole number by a whole always yields a whole number when BOTH  SIDES (in this case, the 2 and the 10) are EVEN numbers.