It is so very simple and quick to get the answer if you use the calculator that comes with your computer. But clearly you are not able to use it so the answer is 8.
80% of 640 = 0.8 x 640 = 512
80
80 multiplied by 640 is 51,200
0.125
0.0125
64
80 x 8 = 640
80 x 8 = 640
The quotient is the solution to a division sum. As such, a single number cannot have a quotient.
640 divided by 8 is 80 with remainder 0.
Let the number be 'x'. Quotient of 80 and x would be : 80/x
640 divided by 8 is 80.