The four solutions that i know are:

1. The most basic: Tan(45)=1
2. 5%4=1 which is same as remainder when 5÷4
3. $\Im^{4}=1$,where $\Im$ is imaginary number.
4. Condone me after reading this...

$\text{FIVE in Roman = V;}$ $\text{FOUR in Roman = IV.So,}$ $\frac{4}{5}=\frac{IV}{V}=I=1$

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

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

$\lfloor{\frac {5}{4}}\rfloor$ or $\lceil{\frac {4}{5}}\rceil$

$5 \oplus 4 = 1$

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

5 mod 4 =1

Greatest integer(5/4)

$\gcd(4,5)=1$

$|cis(45°)|=1$

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

$v_4(5!) = 1$

Gcd(5,4)=1 The easiest one

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

$\Large\color{#D61F06}{\left\lceil\frac{\zeta(5)}{\zeta(4)}\right\rceil}$

totient funtion of 5 / 4

tan(45)=1

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

5 modulo 4=1

Is this possible 5 + 4i^2

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

In programming languages (int)5/4=1

(5/4) × (4/5) = 1.25 x 0.8 = 1 QED

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

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

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

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

5%4

gcd (4,5)=1

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

(1) 5%4

5%4 (mod)=1

5%4.

5%4

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

(5+4)/(5+4)

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...

1. $\lceil \frac{4}{5} \rceil$

tan 45

5/4=1

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

5%4=1

5 modulo 4

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

Cot45= 1

5% 4

⌊ln(5.4)⌋

Log54 to the base 54

5/4 remainder is 1 5mod4 is 1

totient function of 4 x .5

-(4-5)=1 The mirror effect

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

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!

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

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

5-4 floor(5/4) ceiling(5/4) 54/54

1= 5!/(5×4!)

5#/4!

abs(5/4)

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

Mod(5,4)

(4/5)X(5/4)

(5*4)^0 =1

Dim x as integer; x=5/4

5%4=1 what say guys ?

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

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

can i use concantenation?

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

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

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

5%4 = 1

5 \times 4 / 5\times 4

5 modules 4 = 1

5/4

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

5×4=20.Then 20÷20=1

!0

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

(4-5)^{2}

Mine is easier 5/4 x 4/5

((5×4)/5)/4 or ((4×5)/4)/5. They work

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

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

Tan(45)=1

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

4 mod(5)=1

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

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

5%4=1or equivalently 5mod4=1

$\dfrac{\gamma}{4!}$ =$1$

uuhgjjjjk

(5/4)*(4/5)

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

5^4

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

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

[5/4]

a^0 = 1

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

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?

(5×4)/(10×2)

54/54

(54)/(54)

5 x 4 -19

(54)/(54)

5^0 times 4^0 = 1

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