You can
put this solution on YOUR website! for any three consecutive numbers prove that the product of the first and third numbers is always one less than the square of the middle number???
first number = n
middle number = n+1
third number = n+2
product of first and third numbers = n(n+2)
= n²+2n
one less than the square of the middle number = (n+1)² - 1
= (n+1)(n+1) - 1
= n²+2n+1 - 1
= n²+2n
It's proved because both equal n²+2n
Edwin