I think the greatest common factor is 4 x 4.
The place value of 1 is hundred thousands.
The amount of gold coating in millimeters needed for the ring is the difference between the total coating and the coating that has already been applied. From the given above, that would be,
0.03 mm - 0.021 mm = 0.009 mm
Thus, the answer to this question is letter B.
things were not as complicated when I was in middle school.
They are equal because you can measure the percentage as a decimal with a maximum of 1.