The number \(-\frac{2}{5}\) belongs to several sets of numbers in mathematics:
-
Rational Numbers (\(\mathbb{Q}\)): \(-\frac{2}{5}\) is a rational number because it can be expressed as a fraction \(-2/5\), where both the numerator and denominator are integers, and the denominator is not zero.
-
Real Numbers (\(\mathbb{R}\)): Since all rational numbers are also real numbers, \(-\frac{2}{5}\) is also a real number.
-
Negative Numbers: \(-\frac{2}{5}\) is a negative number because it is less than zero.
-
Decimal Numbers: \(-\frac{2}{5}\) can be expressed as \(-0.4\), which is also a decimal number.
-
Irrational Numbers: It does not belong to this set since it can be expressed as a fraction.
To summarize, \(-\frac{2}{5}\) is in the sets of rational numbers, real numbers, negative numbers, and decimal numbers.