you are given a fraction in simplest form. The numerator is not zero. When you write the fraction as a decimal, it is a repeating decimal. Which numbers from 1 to 10 could be the denominator?
The digits 1, 2, 4, 5, 8, and 10 cannot be the denominator; all the others can.
If 1 is the denominator, then there is no decimal.
If 2 is the denominator, it terminates after one decimal place.
If 5 is the denominator, it terminates after one decimal place.
If 10 is the denominator, it terminates after one decimal place.
If 4 is the denominator, it terminates after two decimal places. (4 = 2 x 2, each 2 creates one decimal place)
If 8 is the denominator, it terminates after three decimal places. (8 = 2 x 2 x 2, each 2 creates one decimal place)
The digits 1, 2, 4, 5, 8, and 10 cannot be the denominator; all the others can.
If 1 is the denominator, then there is no decimal.
If 2 is the denominator, it terminates after one decimal place.
If 5 is the denominator, it terminates after one decimal place.
If 10 is the denominator, it terminates after one decimal place.
If 4 is the denominator, it terminates after two decimal places. (4 = 2 x 2, each 2 creates one decimal place)
If 8 is the denominator, it terminates after three decimal places. (8 = 2 x 2 x 2, each 2 creates one decimal place)