The sums of $3$ and $8$ must give a number greater than $13$
65742
Strong Induction: Every natural number $n\geq 8$ can be represented as $n=3k + 5\ell$
140359
Can the sum of finitely many inverses of distinct odd integers $\geq 3$ be 1?
46606
Can an integer of the form $4n+3$ written as a sum of two squares?
48053
Show that 13 divides $2^{70}+3^{70}$
71789
Prove that the sum of digits of $(999...9)^{3}$ (cube of integer with $n$ digits $9$) is $18n$
113119
Use the division algorithm to prove that 3|(n³ + 2n) for all n ∈ ℕ
93094
How do I solve this problem on maximizing sum modulo a given number?
151179
Finding the value of $\sum k/3^k$
158124
Sum of all the positive integers problem
87181
For any given set of 13 distinct real numbers, prove we can always find two numbers $x$ and $y$ that $0<\frac{x-y}{1+xy}\leq 2-\sqrt{3}$.
131708
Sum of powers of natural numbers
148745
Determine if a number is the sum of two triangular numbers.
49851
when the sum of some fractions be $1$
94209
Prove by contradiction that every integer greater than 11 is a sum of two composite numbers
91105
For every $n\ge3$ there exists $n$ different integers $a_1,...,a_n$ so that $\frac{1}{a_1}+\frac{1}{a_2}+...+\frac{1}{a_n}=1$
44577
Finding a formula to sum natural numbers up to $n$
107395
If the sum of $n$ cubes is zero, then the sum must be no larger than $\frac n3$.