Venn Diagram - Number System:

The number is 45.

Observe the Venn Diagram:

\
•  The number is a natural number (N).
\
•  The number is a rational number (Q).
\
• The set of whole numbers (W), integers (Z) are subsets of rational numbers (Q).
\
•  All rational numbers (Q) are real numbers (R).
\

The number 45 belongs to N, W, Z, Q, and R.