# The Four Fours Problem

James Chegwidden

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posted 12 years ago

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Here is a problem that I found in a rec math book from the 1950's

This is an old problem consisting of expressing successive integers (to a limit) in appropriate mathematical form, using only 4 (four) fours (4's) in each expression together with any necessary signs.

Note: My math collegues had a field day with this problem.

Examples: 1 = 4/4 * 4/4

10 = (44 -4)/4

So for what are the first twenty numbers written in only 4 4's.

This is an old problem consisting of expressing successive integers (to a limit) in appropriate mathematical form, using only 4 (four) fours (4's) in each expression together with any necessary signs.

Note: My math collegues had a field day with this problem.

Examples: 1 = 4/4 * 4/4

10 = (44 -4)/4

So for what are the first twenty numbers written in only 4 4's.

Author and Instructor, my book

Melvin Menezes

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Greg Harris

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posted 12 years ago

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this is assuming i can use mod(x,y) and !

1 = (4/4)*(4/4)

2 = (4*4)/(4+4)

3 = ((4*4)-4)/4

4 = (4*(4-4))+4

5 = MOD((4/4),4)+4

6 = (SQRT(4))+(4-4)+4

7 = ((4+SQRT(4))+(4/4))

8 = ((4+4)*4)/4

9 = (4+4)+(4/4)

10 = (4!+SQRT(4)-4*4)

11 = (4!/SQRT(4))-(4/4)

12 = (4!+4-4*4)

13 = (4!/SQRT(4))+(4/4)

14 = (4*4)-(4/SQRT(4))

15 = (4*4)-(4/4)

16 = (4/4)*(4*4)

17 = (4*4)+(4/4)

18 = ((4*4)+4)-(SQRT(4))

19 = (4!-4-4/4)

20 = (4*(4/4+4))

1 = (4/4)*(4/4)

2 = (4*4)/(4+4)

3 = ((4*4)-4)/4

4 = (4*(4-4))+4

5 = MOD((4/4),4)+4

6 = (SQRT(4))+(4-4)+4

7 = ((4+SQRT(4))+(4/4))

8 = ((4+4)*4)/4

9 = (4+4)+(4/4)

10 = (4!+SQRT(4)-4*4)

11 = (4!/SQRT(4))-(4/4)

12 = (4!+4-4*4)

13 = (4!/SQRT(4))+(4/4)

14 = (4*4)-(4/SQRT(4))

15 = (4*4)-(4/4)

16 = (4/4)*(4*4)

17 = (4*4)+(4/4)

18 = ((4*4)+4)-(SQRT(4))

19 = (4!-4-4/4)

20 = (4*(4/4+4))

what?

Melvin Menezes

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Greg Harris

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Mark Herschberg

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Greg Harris

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posted 12 years ago

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actually, after googling around, this guy says you can go from 0 to 40,000.

here is a short list that goes from 0 to 1,000.

not quite the same as what i came up with... and i did not think about using sin, cos, gamma, etc.

here is a short list that goes from 0 to 1,000.

not quite the same as what i came up with... and i did not think about using sin, cos, gamma, etc.

what?

John Lee

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Greg Harris

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John Lee

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It is sorta covered in the JavaRanch Style Guide. |