I got you.
You don't understand the fact that there the standart formula is used for the displacement -- D=a*t^2/2
Please add all the digits in the column (D) and you will get your figure (in each line the movement is indicated for exactly this one second, and not for the total during during this time) So the total displacement during all 5 secons (i.e. the displacement for 1st second (4.9m)+the displacement for 2nd second (14.7m) + so on )=122.5m! (according to the standard current formula) = 122.5m ! (according to the standard current formula)