Negative number: a number less than 0. Negative number is a mathematical term. Numbers less than 0 are called negative numbers, and negative numbers and positive numbers represent quantities with opposite meanings. Negative numbers are marked with negative sign (minus sign) "-"and positive numbers, such as _2, which represent the reciprocal of 2. 2. Positive number: a number greater than 0. Positive number is a mathematical term. Numbers greater than 0 are called positive numbers, and 0 itself is not a positive number. Positive numbers and negative numbers represent quantities with opposite meanings. Positive numbers are usually preceded by a "+"symbol, which can usually be omitted. Negative numbers are marked with a negative sign "-"and a positive number, such as _2, which stands for the antonym of 2. 0 is neither positive nor negative.