**You can use any Mathematical expression,any method suitable...stupidity is on.**

**But the challenge is you cannot use any other numbers,you can use 5 and 4 only once and you cannot use '**-**'(minus) sign.**

I know 4 possible methods...Can you find still more ?

No vote yet

1 vote

×

Problem Loading...

Note Loading...

Set Loading...

Easy Math Editor

`*italics*`

or`_italics_`

italics`**bold**`

or`__bold__`

boldNote: you must add a full line of space before and after lists for them to show up correctlyparagraph 1

paragraph 2

`[example link](https://brilliant.org)`

`> This is a quote`

Remember to wrap math in \( ... \) or \[ ... \] to ensure proper formatting.`2 \times 3`

`2^{34}`

`a_{i-1}`

`\frac{2}{3}`

`\sqrt{2}`

`\sum_{i=1}^3`

`\sin \theta`

`\boxed{123}`

## Comments

Sort by:

TopNewestThe four solutions that i know are:

Tan(45)=15%4=1which is same asremainder when 5÷4where \(\Im\) is imaginary number.\(\text{FIVE in Roman = V;}\) \(\text{FOUR in Roman = IV.So,}\) \[\frac{4}{5}=\frac{IV}{V}=I=1\]

Log in to reply

\(5^{\mu(4)}\) is also posible, where \(\mu\) defines the MOBIUS function.

Log in to reply

Yes...thats right👍👍 Good use of MOBIUS function

Log in to reply

even cot(45)=1

Log in to reply

even cotan(45)=1

Log in to reply

yup..right.👍👍

Log in to reply

5 (mod 4) = 1

Log in to reply

\(\frac{d}{dx}(x+54)=1\)

Log in to reply

5-4=1

Log in to reply

Woahh, allaww

Log in to reply

Same thing as 5-4 but looks different \(\int _{ 4 }^{ 5 }{ dx } = 1\) Lol. X'D

Log in to reply

yess....even this is possible👍👍

Log in to reply

Nicely done, didn't see that.

Log in to reply

\(\dfrac { Gamma(5) }{ 4! } =1\)

Log in to reply

Could u explain what the gamma() function's purpose

Log in to reply

The factorial \(n!\) is originally defined only for positive integers \(n\), so 18th century mathematicians came up with an integral \( Gamma(t)=\Gamma (t)=\int _{ 0 }^{ \infty }{ { x }^{ t-1 }{ { e } }^{ -x }dx } \) that has properties similar to the factorial, but defined for all real and complex numbers \(t\) (except \(0\) and negative integers). It works out that \(\Gamma (t)=(t-1)!\). A very versatile function, the gamma function is one of the most widely used functions in mathematics.

Log in to reply

Log in to reply

Log in to reply

Can you please tell me what is it's actual meaning? Like 8! means 8(8-1)(8-2)......(8-7) so what is the meaning of -2! ?? @Michael Mendrin

Log in to reply

yeah...never thought of this...👌👍

Log in to reply

Aw yes. :-)

Log in to reply

\(\lfloor{\frac {5}{4}}\rfloor\) or \(\lceil{\frac {4}{5}}\rceil\)

Log in to reply

In a similar way, \( \lfloor \sqrt[5]{4} \rfloor, \lfloor \sqrt[4]{5} \rfloor \) etc will also work.

Log in to reply

Or \(\lfloor{\sqrt{\frac {5}{4}}}\rfloor\) and \(\lceil{\sqrt{\frac {4}{5}}}\rceil\)

Log in to reply

Thas possible...greatest integer function..👍

Log in to reply

5 and 4 are used twice

Log in to reply

No, they're not. They are used only once in each expression. I have written them separately.

Log in to reply

Log in to reply

Log in to reply

Log in to reply

Log in to reply

\(5 \oplus 4 = 1\)

Log in to reply

You need to describe the modulo number i.e.\(5 \bigoplus_84\) for which an extra 8 is required.

Log in to reply

It's not modulo, but an XOR operation, :)

Log in to reply

Log in to reply

Whats the sign between 5 and 4???

Log in to reply

this made my day....ahahahah

Log in to reply

\[ \ln \left({\frac{\exp{(5)}}{\exp{(4)}}}\right)=1 \]

Log in to reply

Wow....superb !!Gud one👌👌

This one's right.

Edit it to Ln instead of log...

Log in to reply

I wrote it ln then changed it to log, thought that in english countries, log refers to the natural logarithm. Anyway I'm editing it again :)

Log in to reply

However Ln seems better...:)

Log in to reply

5 mod 4 =1

Log in to reply

\(v_4(5!) = 1\)

Log in to reply

Speechless.......

Log in to reply

What is \(\nu\) function ???

Log in to reply

Highest power of a prime that divides something.In this case it is not used properly, because 4 is not a prime.

Log in to reply

Log in to reply

Log in to reply

\( \frac{\phi(5)}{4} = 1\)

Log in to reply

On a similar note of numerical functions, \(d(4)-d(5)=1\) where \(d(n)=\)the number of positive divisors of n.

Log in to reply

yup...another solution..

Log in to reply

\(\gcd(4,5)=1\)

\(|cis(45°)|=1\)

Log in to reply

yeah....cool solution...gud one ✌👍

Log in to reply

Greatest integer(5/4)

Log in to reply

Yes..this one is possible.

3 more ways are possible.

Log in to reply

Signum(5+4), Signum(5×4) Signum(5÷4)

Log in to reply

Again,find the other ways...

Log in to reply

\[\Large\color{red}{\left\lceil\frac{\zeta(5)}{\zeta(4)}\right\rceil}\]

Log in to reply

signum(45),or anything which invlove 4 and 5(but real)

Log in to reply

yes...signum function is possible...It is a function which always gives 1 for any constant.

Log in to reply

Gcd(5,4)=1 The easiest one

Log in to reply

In programming languages (int)5/4=1

Log in to reply

\(\frac{d(\sigma(\sigma(\sigma(\sigma(\sigma(5))))))}{d(\sigma(\sigma(\sigma(\sigma(\sigma(4))))))} = 1\)

Log in to reply

Lawl is that too much... =="

Log in to reply

Where \(d(n)\) is the number of divisors of n and \(\sigma(n)\) is the sum of divisors of n.

Log in to reply

Is this possible 5 + 4i^2

Log in to reply

This gives 1 but extra 2 cant be used as in i^2.

Log in to reply

Just write it like this: \(5+4i \times i=1 \)

Log in to reply

Log in to reply

Log in to reply

Log in to reply

5 modulo 4=1

Log in to reply

tan(45)=1

integer(5/4)=1 (we use in C language int(a/b) to get integer quotient)

Log in to reply

totient funtion of 5 / 4

Log in to reply

yeah...its possible

(Totient of 5)/4

Log in to reply

⌊ln(5.4)⌋

Log in to reply

5% 4

Log in to reply

Cot45= 1

Log in to reply

5 = 101 (binary notation) 4 = 100 So. 5 xor 4 = 001

Log in to reply

5 modulo 4

Log in to reply

5%4=1

Log in to reply

5/4=1

Solution : int a=5,b=4,c; c=a/b; (hence c=1)

Log in to reply

Ya....and even c=5%4

Log in to reply

tan 45

Log in to reply

Log in to reply

Hi Vinay this discussion is a good food for thought....Next

Try to express 0 to 9 numerals using the digit 3 only. One hint is using factorial may come in handy...

Log in to reply

Thank you...

Generating 0 to 100 will be more interesting..I think you should post a note on it...

Log in to reply

Also post its link in this note as a comment...

Log in to reply

Here, I've created a note for this.

Log in to reply

(5+4)/(5+4)

Log in to reply

you've broken the rules

Log in to reply

sum to infinity of i=1 (4*5^-i) //sorry but i don't know how to write the notation

Log in to reply

\(\sum_{i=1}^{\infty}4×5^{-i}\)

The expression gives the value 1 but extra

1 and \(\infty\) cannot be used.Log in to reply

5%4

Log in to reply

5%4.

Log in to reply

5%4 (mod)=1

Log in to reply

(1) 5%4

Log in to reply

ceil(4/5),floor(5/4)

Log in to reply

gcd (4,5)=1

Log in to reply

what does ceil and floor mean

Log in to reply

5%4

Log in to reply

No offence to maths but 4 = IV and 5 = V in roman numerals. So IV/V = I ( after cancelling V on both sides) = 1

Log in to reply

The most obvious \(gcd(5,4)=1\)

Also, \(\frac{\varphi(5)}{4}=1\)

Log in to reply

yep..The gcd(5,4) is the most obvious.

Log in to reply

small omega of 5 / small omega of 4 ( note small omega counts the number of distinct prime factors )

Log in to reply

(5/4) × (4/5) = 1.25 x 0.8 = 1 QED

Log in to reply

The condition is you cannot use 5 and 4 more than once.

Log in to reply

Ah fair enough

Log in to reply

\(\sin{(4+5)}={\lceil}{0.3955...}{\rceil}={\boxed{1}}\)

Log in to reply

(5/4)*(4/5)

Log in to reply

uuhgjjjjk

Log in to reply

\(\dfrac{\gamma}{4!}\) =\(1\)

Log in to reply

5%4=1or equivalently 5mod4=1

Log in to reply

\(5\quad mod\quad 4,\quad \left\lfloor \frac { 5 }{ 4 } \right\rfloor ,\quad \left\lceil \frac { 4 }{ 5 } \right\rceil ,\quad round\frac { 5 }{ 4 } ,round\frac { 4 }{ 5 } \\ \frac { \Gamma (5) }{ 4! } ,\quad cot(45deg)\)

Log in to reply

5%4 = 1 ie., 5 modulus of 4 = 1

Log in to reply

4 mod(5)=1

Log in to reply

\(y\quad =\quad 54x\\ then\\ { [\frac { { d }^{ 2 }y }{ d{ x }^{ 2 } } ] }!\\ =1\)

Log in to reply

You cannot use 2...

Log in to reply

Tan(45)=1

Log in to reply

( 5 / 4 ) * ( 4 / 5 ) or ( 5 / 5 ) / (4 / 4) something like this :D

Log in to reply

Nope...you cant use 5 and 4 two times.

Log in to reply

(5^2+4^2+4)/45

Log in to reply

((5×4)/5)/4 or ((4×5)/4)/5. They work

Log in to reply

Mine is easier 5/4 x 4/5

Log in to reply

Comment deleted Jun 29, 2014

Log in to reply

Sorry, it is supposed to be (5X4) instead of (54)

Log in to reply

(4-5)^{2}

Log in to reply

'-' sign should not be used and extra numbers cant be used.

Log in to reply

The 3 solution i no is Lint of 4/5 Zint of 5/4 Tan45

Log in to reply

!0

Log in to reply

5×4=20.Then 20÷20=1

Log in to reply

5^{0} \times 4^{0}

Log in to reply

Good one but you used 0

Log in to reply

can you please explain the notation....??

Log in to reply

It is 5 raised to 0 divided by 4 raised to 0

Log in to reply

Log in to reply

5/4

Log in to reply

5 modules 4 = 1

Log in to reply

5 \times 4 / 5\times 4

Log in to reply

5 and 4 can be used only once...

Log in to reply

5%4 = 1

Log in to reply

Write a comment or ask a question... 5!/(5*4!)=1

Log in to reply

No two times 5

Log in to reply

Using Exclusive OR gate. 5=101(b) 4=100(b) In Ex-OR logic output will high if input level is different. Here after computation output is 001(b) its decimal is 1

Log in to reply

can i use concantenation?

\( \frac{(5|4)}{54} = \boxed{1} \)

Log in to reply

You can use concatenations

But two times 5 and 4 not allowed.

Log in to reply

(cos 5) ^2 + (sin 5) ^2 = 1

Log in to reply

2 cannot be used.

Log in to reply

We can use 5 XNOR 4 == 1 101 XNOR 100 == 1 What you say?

Log in to reply

5 xnor 4 = \(\overline{101\bigoplus100} = \overline{001}=110\)

But 5 xor 1 = 001.

Log in to reply

Sorry my fault, It's not a valid solution. Solution should be like, we can not only use 5 and 4? ryte?

Log in to reply

Log in to reply

5%4=1 what say guys ?

Log in to reply

Dim x as integer; x=5/4

Log in to reply

(5*4)^0 =1

Log in to reply

0 not allowed and

5 and 4 not allowed twice.

Log in to reply

(4/5)X(5/4)

Log in to reply

Mod(5,4)

Log in to reply

floor(ln(5)/ln(4)) and ceil(ln(4)/ln(5)) I hope ln(x), the natural logarithm, is acceptable here.

Log in to reply

abs(5/4)

Log in to reply

Why not 5 mod 4

p^2(Actually p^2 is Piyush Patnaik)

Log in to reply

5#/4!

Log in to reply

1= 5!/(5×4!)

Log in to reply

5 and 4 only once...

Log in to reply

5-4 floor(5/4) ceiling(5/4) 5

4/54Log in to reply

(factorial(5)/factorial(4))/5

Log in to reply

*5 mod 4 =1; *(5+4) mod 4=1;

Log in to reply

5 (mod 4) is possible but (5+4)(mod 4) is not possible...only one time 5...

Log in to reply

oh....kk sry

Log in to reply

5%4 = 1 :P .. The % is the modulus sign.. It gives the remainder of 2 non- floating numbers ! As the remainder for floating numbers is zero always!

Log in to reply

5%4 =1 , 5\(\oplus\)4 = 1, \(\lfloor\frac {5}{4} \rfloor\) =1, \(\lceil \frac {4}{5} \rceil\) =1 ,

Log in to reply

-(4-5)=1 The mirror effect

Log in to reply

No minus sign.........

Log in to reply

totient function of 4 x .5

Log in to reply

here

.5 is not possible...0Log in to reply

5/4 remainder is 1 5mod4 is 1

Log in to reply

5%4=1...Yes,thats one of the ways that I knew.

Log in to reply

Log54 to the base 54

Log in to reply

5 and 4 can be used only once..

Log in to reply

(5 xor 4) in binary

Log in to reply

Log in to reply

How about .5 repeated plus .4 repeated? Does that break the rule for multiple usages of the digits if the horizontal line notation is used?

Log in to reply

yep..breaks the rule.

Log in to reply

f\left( x \right)=x\ f(5)-f(4)=1

Log in to reply

a^0 = 1

Log in to reply

Nope....0 not to be used.

Log in to reply

[5/4]

Log in to reply

Taking (5+4)- (4+4) = 1

Log in to reply

54/54 =1,45/45=1,5%4=1,(5*5)%4!

Log in to reply

5^4

Log in to reply

(5

4)/(54)Log in to reply

5 x 4 -19

Log in to reply

nvm... Can't have a - sign

Log in to reply

(5

4)/(54)Log in to reply

54/54

Log in to reply

(5×4)/(10×2)

Log in to reply

10 and 2 cant be used.

Log in to reply

I'LL BLOW ALL OF YOUR MINDS!!!! |4-5|=1

Log in to reply

5^0 times 4^0 = 1

Log in to reply

Wrong answer 0 can't be used

Log in to reply

nope...0 cant be used.

Log in to reply