A quarter times five is: 1/4*5=5/4, the denominator is still 4, and the denominator is 5. That's five quarters. The second method of multiplying 20 by 1/4 is the same as the previous method, except that the numerator is changed to 20, but here the numerator and denominator of 20 are divisible, that is, 20* 1/4=20/4, and the divisor is equal to 5. When encountering similar problems, remember to keep the original denominator unchanged and multiply it by the multiplicand or multiplier. If the denominator of the upper and lower numerator can be reduced, remember to remove the same divisor.