Integers and polynomials with coefficients from a finite field almost the same thing. For example, the number 2019 can be expressed as 2 * 10^3 + 0 * 10^2 + 1 * 10^1 + 9 * 10^0, or 2x^3 + x^1 + 9x^0 where x=10. Number is a special case of a polynomial with a coefficients from a finite field.

They are different things really, but close enough to have much in common.

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