4:30

The sum of an arithmetic sequence with 600 terms is 120000; Last term=393 Find the common difference

19:26

An interesting approach to the Basel problem!

10:51

Find smallest x∈N satisfying τ(30x) = 30

8:59

Find all natural numbers n Such That 36^n - 6 equals the product of 3 consecutive natural numbers

3:43

Euclid's Perfects and Mersenne's Primes (visually)

9:34

Show φ(n^2 ) = nφ(n) ∀ n ∈ N

5:45

What does a ≡ b (mod n) mean? Basic Modular Arithmetic, Congruence

13:11

بكل جراءة بطريرك سوريا يعلنها صراحة وبكل وضوح