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## Question

Using only four nines(9), make the number 100 in any form. You may use +, -, x, and /.

Don't think too hard. This is a simple one.

99 and 9/9

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99+9/9

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99 + (9/9=1)=> 99+1=100

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Using only four nines(9), make the number 100 in any form. You may use +, -, x, and /.

Don't think too hard. This is a simple one.

99+9/9=100

Edited by dhanu
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Using only four nines(9), make the number 100 in any form. You may use +, -, x, and /.

Don't think too hard. This is a simple one.

99+9/9=100

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The key was the clue to "keep it simple"

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9*9=81 81+9=90 90+9=99 99*9=891 891+9=900 900/9=100!

I only used 7 9s!

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9*9=81 81+9=90 90+9=99 99*9=891 891+9=900 900/9=100!

I only used 7 9s!

Nice try there is an easier way though.

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99.99.... [borrowing the use of periods, of course

]
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99.99.... [borrowing the use of periods, of course
]

Needs to be exactly 100.

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Needs to be exactly 100.

he's just having fun...let's see what i can do!!

9+9+9+9+9+9+9+9+9+9+9+9+9/9.

9*9+9/(9/9)+9+9/9

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Needs to be exactly 100.

Technically, 99.99... (repeating) is equal to 100 in the real numbers system.

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I can do this with only 3 9s

((9/9)+9)=10 and 10 is 100 in the -1 power, a form of 100

Wait i found easier way, 99+9/9= 100!!!!!!!!

Edited by bonanova
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Needs to be exactly 100.

Actually, that does equal 100.

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Actually, that does equal 100.

only when rounded to the nearest hundredth

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only when rounded to the nearest hundredth

Actually, only when it's not rounded to the nearest anything.

Consider:

1/3 = .33 ....

That equality is true only when the 3's go on indefinitely.

If they're truncated [terminated] after n decimal places, the equality fails.

Now multiply both sides by 3:

1 = .99 ....

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Actually, only when it's not rounded to the nearest anything.

Consider:

1/3 = .33 ....

That equality is true only when the 3's go on indefinitely.

If they're truncated [terminated] after n decimal places, the equality fails.

Now multiply both sides by 3:

1 = .99 ....

i am talking about 99.99 so it is different because i said four nines, but i like the thought

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i am talking about 99.99 so it is different because i said four nines, but i like the thought

99.99 ... uses only four nines.

And some periods, which in fairness the OP does not permit: only 9's and +, -, x, /

Consider that "...." is a mathematical notation for infinite repetition.

Thus any number, including two, 9's suffice to stand for an infinite number of 9's.

99.9 .... = 99.99 .... = 99.999 .... = 99.9999 .... = 100.

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9/.9 x 9/.9 = 100

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99 + 9/9 = 100

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