Is $1 + 2 + 3 + \dots = -\frac{1}{12}$ really true?
4340
Why does $1+2+3+\cdots = -\frac{1}{12}$?
140086
Does $3-4+1$ equal $0$ or $-2$.. or maybe $2$?
77764
Is "$a + 0i$" in every way equal to just "$a$"?
91410
Finding the sum of this series: $1+\frac 12 + \frac 13 + \cdots + \frac 1{50}$
56169
What mistakes, if any, were made in Numberphile's proof that $1+2+3+\cdots=-1/12$?
148745
Determine if a number is the sum of two triangular numbers.
66061
Why is the formula for calculating euler totient true?
113593
How can I prove that $\frac{n^2}{x_1+x_2+\dots+x_n} \le \frac{1}{x_1}+ \frac{1}{x_2} +\dots+ \frac{1}{x_n}$?
16967
Sum : $\sum_{n=0}^\infty \frac{(-1)^n}{(2n+1)^3}$
104542
Evaluate $\frac{1}{3}+\frac{1}{4}\frac{1}{2!}+\frac{1}{5}\frac{1}{3!}+\dots$
23836
Rigorous proof that $\frac{1}{3} = 0.333\ldots$
119107
Is it true that $\sum_{k=3}^{n}\binom{n}{k}\binom{k}{3} = \binom{n}{3}\binom{n-3}{k-3}$?
41645
Checking my understanding: $1 - 1 + 1 - 1 + 1 - ... = \frac{1}{2}$
95786
Sum $\frac{1}{6} + \frac{5}{6\cdot 12} + \frac{5\cdot 8}{6\cdot 12\cdot 18} + \frac{5\cdot 8\cdot 11}{6\cdot 12\cdot 18\cdot 24}+\ldots$
155611
Sum of series $\frac{1}{2 \cdot 3 \cdot 4} + \frac{1}{4 \cdot 5 \cdot 6} + \frac{1}{6 \cdot 7 \cdot 8} + \cdots $
30600
Why does $\tan^{-1}(1)+\tan^{-1}(2)+\tan^{-1}(3)=\pi$?
138193
Why is $\sqrt {12} = 2 \sqrt 3$?