Error in variance estimation

Hello !
Can anyone please help me why is he not taking the square of the values before adding them (as per the formula)?

Can you give the video title and time mark?

I believe he is taking the square of the difference between the mean (x hat) and each of the values in the sample set. If we look at row 2 for example: x= 1, 2 mean=1.5. So ((1-1.5)**2)+((2-1.5)**2) == (.25)+(.25) == 0.5 >> 0.5/(2-1) == 0.5

It seems to be the case for each row, then take the average of the 9 rows for the total estimated variance >> 6/9 == 0.6667.