what is 0.0000624 rounded to the nearest 10th?
A tenth is 0.1, so to the nearest tenth means to the 1st decimal place.
That means that you only consider ths 2nd decimal place. So look at the following value,
0.00 (the 1st two decimal places of the number 0.0000624)
If the 2nd decimal place digit is greater than or equal to five, then the 1st decimnal place is rounded up by one, else it is left as it is.
Since the 2nd decimal place is zero, then no change is made to the 1st decimal place.
So to the nearest tenth 0.0000624 has the valuue 0.0