Here are some purely visual proofs of that fact: http://gauravkumar.tech/math/visual-proofs/sum-of-first-n-natural-numbers.html http://gauravkumar.tech/math/vis

Here are some purely visual proofs of that fact: http://gauravkumar.tech/math/visual-proofs/sum-of-first-n-natural-numbers.html http://gauravkumar.tech/math/visual-proofs/sum-of-first-n-na...