In the two questions, we first replace the division with multiplication with flipping the fraction after the division sign, secondly we analyze any equation that needs analysis to simplify it, thirdly, to simplify the fraction by deleting the numerator and the similar denominator .
520 CD's because of the 9 months and we add 30 time 9 we erase the 0 and multiply the 3 with the 9 it will be 27 right we add the zero because the originla number is 30