Is -5 a irrational number?

1 Answer
Aug 11, 2016

No, #-5# is an integer.

Explanation:

There are various number types (natural, whole, integer, rational, real and irrational).

Natural numbers are "counting numbers" like #1, 2, 3, 4#.

Whole/counting are like natural numbers, except that they start from #0#.

Integers are all the whole numbers - positive, negative numbers and 0, but not fractions or decimals.

(https://socratic.org/prealgebra/negative-numbers-and-absolute-value/negative-numbers-1),

Rational numbers can be written as #a/b, b !=0#
#-5 " can be written as " (-10)/2, "so it is rational"#
Rational numbers include all the integers, all the vulgar fractions, all the terminating decimals (ones that end, like #0.85#, and all the recurring decimals, unlike #pi#).

Irrational numbers are infinite decimals which do not recur like #pi#, #sqrt2# or #sqrt20#

Non-real/Imaginary numbers do not exist on the numberline,
Numbers like #sqrt(-50), sqrt(-16), 4i#.

#-5# in an integer and is not irrational.