When simplifying you need to be able to divide both the top and bottom number in the fraction by one of their factors. A number will be fully simplified when they become a prime number or have one as the numerator.
They are any number in front of a variable so like 4x 7y or 8z. 4, 7 and 8 are the coefficients. A number by itself is a constant. For example 3, 1 and 9 are constants.
