Descartes' rule of signs
"The rule states that if the terms of a single-variable polynomial with real coefficients are ordered by descending variable exponent, then the number of positive roots of the polynomial is either equal to the number of sign differences between consecutive nonzero coefficients, or is less than it by an even number. Multiple roots of the same value are counted separately."
As a corollary of the rule, the number of negative roots is the number of sign changes after multiplying the coefficients of odd-power terms by −1, or fewer than it by an even number. This procedure is equivalent to substituting the negation of the variable for the variable itself.
I'm sorry for this question. I think is more an English one than a mathematical matter. I didn't understand the meaning of the phrases: "...less than it by an even number" and "fewer than it by an even number"
So if the change signs are $5$ or $6$ which "even number" he meant?