Write an expression to show the difference between 4k+5 and 3k -4

Abox contains 1 plain pencil and 4 pens. a second box contains 5 color pencils and 5 crayons. one item from each box is chosen at random. what is the probability that a plain pencil from the first box and a color pencil from the second box are selected? write your answer as a fraction in simplest form.

If private savings 'v' = 0.75s and total savings 's' equals $4.20 billion, solve for public and private savings.

What is always true when two whole numbers are subtracted?