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Using four sevens (7) and a one (1) create the number 100. Except the five numerals you can use the usual mathematical operations (+, -, x, , root and brackets ().

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100 - solution

100 = 177-77 = (7+7)x(7+(1:7))

I do not know other solutions.

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• 2 months later...
• Replies 52
• Created

#### Popular Days Another solution would be

take 7-7=0

7-7=0

and put the one in front of it which would be100

##### Share on other sites concatenation isn't a mathematical operator >

##### Share on other sites 77+(7+7+7)+(7/7)+1

100=77+23

=77+(21)+(2)

=77+(7+7+7)+(1+1)

=77+(7+7+7)+((7/7)+1)

##### Share on other sites You're only allowed 4 sevens...not 7 sevens...

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• 2 weeks later... uhh its just 7^2+7^2+1+1

##### Share on other sites uhh its just 7^2+7^2+1+1

That's two 7's, two 2's, and two 1's...not four 7's and one 1.

##### Share on other sites it is 4 sevens just not 1 one. (7x7)=7^2.

##### Share on other sites 7 x (7+7) + cubed root of (7+1) = 100

7 X 14 + cubed root of 8

98 + 2 = 100

##### Share on other sites Hi all,

I thought of a unique solution...

By inverting 2 of the 4 - 7's

1 L7 L7

Ha Ha ! !

##### Share on other sites Editted - i found the flaw in my answer, nevermind...

##### Share on other sites (7 + 1/7) (7+7)

##### Share on other sites Clever!

I've done a challenge a bit like this: create all numbers from 1-200 using 4 4s and the following mathematical operators: +, -, /, x, ! (factorial), !! (double factorial), INT, MOD, SQRT, ^ (power). You can't do squares etc. - if you use powers the number has to be raised to its fourth power (or 4x4th power etc.).

It is much harder than it looks like!

##### Share on other sites (7 + 1/7) (7+7)

SWEET!!

##### Share on other sites ##### Share on other sites Are you being sarcastic? It was mannu who posted that answer.

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• 2 weeks later... ERROR

##### Share on other sites What do you mean "error"? Are zou spamming?

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• 4 weeks later... (7*7)+7+7+1 = 100

BTW, it's octal

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• 2 weeks later... (7*7)+(7*7)+1=100

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• 2 weeks later... (7*7+1) (7+7)/7 = 100

##### Share on other sites (7*7)+(7*7)+1=100

Um...that's only 99 not 100.

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• 3 weeks later... (7*7+1) (7+7)/7 = 100

nice, but only four 7s are allowed

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• 2 weeks later... 100 - Back to the Number Puzzles

Using four sevens (7) and a one (1) create the number 100. Except the five numerals you can use the usual mathematical operations +, -, x, :, root and brackets ().

The language should be changed in the problem. Drop the word "EXCEPT" and replace it with the phrase "In addition to".

-Brett

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100 - Back to the Number Puzzles

Using four sevens (7) and a one (1) create the number 100. Except the five numerals you can use the usual mathematical operations +, -, x, :, root and brackets ().

The language should be changed in the problem. Drop the word "EXCEPT" and replace it with the phrase "In addition to".

-Brett

thanks, I have edited the puzzle ... feel free to check the wording in other puzzles as well

##### Share on other sites This topic is now closed to further replies.