There are six common sets of numbers.

Natural (Counting) Numbers:

Whole Numbers: Natural Numbers and

Integers:

Rational Numbers: Integers, Fractions, and Terminating or Repeating Decimals

Irrational Numbers: Non Terminating or Non Repeating Decimals

Real Numbers: Rational Numbers and Irrational Numbers

Determine which sets the number fits into.

Irrational Numbers, Real Numbers

Determine the Type of Number square root of 51