A decimal and a fraction are basically cousins. When we say the decimal 0.81 we say 81 hundredths. Basically what we are saying is the decimal in fraction form. The first number 81 will be the numerator and the last number hundredths will be the denominator which then give us the fraction of 81/100. The fraction 81/100 is already in simplified to the lowest terms. So that is the answer. I hope this helps!