Why does 2+2 equal to 4?
62072
Is $2+2=4$ an identity?
153241
Four different positive integers a, b, c, and d are such that $a^2 + b^2 = c^2 + d^2$
42446
Simple Elementary Algebra Equality
102306
Why is this simple calculation of two doubles inaccurate?
27969
Why does $\frac{1}{x} < 4$ have two answers?
64985
Get the numbers from (0-30) by using the number $2$ four times
34913
Why does basic algebra provide one value for $x$ when there should be two?
69943
why is ${n+1\choose k} = {n\choose k} + {n\choose k-1}$?
87846
If $\gcd (x,4) = 2$ and $\gcd(y,4) = 2$ then $\gcd(x+y,4) = 4$
146753
Find $x$ such that $(x^2 + 4x + 3)^x + (2x + 4)^x = (x^2 + 4x + 5)^x$
73099
Why is $d(x^2)= 2xdx$?
70660
Why is $\sqrt{8}/2$ equal to $\sqrt{2}$?
73307
Why is the last digit of $n^5$ equal to the last digit of $n$?
53725
Factor $(x+y)^4+x^4+y^4$
137970
$2 + 2 = 5$ (Fake proof, or ?)
23270
The sum of powers of two and two's complement – is there a deeper meaning behind this?
33184
Something strange about $\sqrt{ 4+ \sqrt{ 4 + \sqrt{ 4-x}}}=x$ and its friends