62 rows of 9 chairs.
The questions asks about how many, so we are estimating. So we will round 62 down to 60 and 9 up to 10.
So, 60 rows of 10 chairs.
Then we multiply 60 * 10 to get 600.
The exact amount of 62*9 = 558, but we are estimated so our estimation would be there are about 600 chairs.