Answer :
The answer is 5 1/4, because 4 goes into 21, 5 times, adding 1 whole number making it 5. also, 21-20=1 (just giving all information), and, the denominator always stays the same, but not needed for multiplying and dividing (cuz dividing is almost the same as multiplying). So the answer to ur question is 5 1/4. Hope it helps! ;)