The quotient is the result of dividing one number by another.
To divide an integer (whole number) into a decimal using simple (rather than long) division (assuming you know your 12 times table), divide as you would if there were no decimal point, but as you work out the result write (or imagine) each digit over the dividend (what you're dividing into) in the appropriate place.
So in this case 12 goes into 64 5 times, and you write 5 over the 4. Then you have 4 over making 48, which divides by 12 exactly 4 times. Write 4 over the 8.
The only digit that doesn't have anything written over it is the 6. Write zero over it and you have the answer: .054. It's customary to protect the decimal point by writing a zero in front: 0.054.
If the number hadn't been exactly divisible by 12 you just carry on bringing down zeroes to continue the division indefinitely or until you're fed up or you have the required number of decimal places.
OK?