Play with sum - shortcuts

• Sum of first n natural numbers= n(n+1)/2
• Sum of first n even numbers=n(n+1)
• Sum of first n odd numbers=n^2
• Sum of square of first n natural numbers=[n(n+1)(2n+1)]/6
• Sum of square of first n even natural numbers= [2n(n+1)(2n+1)]/3
• Sum of square of first n odd numbers=[n(4(n^2) - 1)]/3
• Sum of cube of first n natural numbers={[n(n+1)]/2}^2
• Sum of cube of first n even natural numbers=2[n(n+1)]^2
• Sum of cube of first n odd natural numbers= (n^2)*[2(n^2)-1]