A real number can be negative, positive, irrational, whole, rational, a fraction, a decimal, etc. Almost every number is real. Numbers that are not real are imaginary numbers. Examples of imaginary numbers are infinity and the square root of 1. An imaginary number, when squared, gives a negative result.
Box A is 4. 4 is 5% of the total boxes. 5% = 1/20, so multiply whatever number that's 5% of the total by 20 to get the total. 4 x 20 = 80. There are 80 marbles total. Hope this helps!
