NumberQ
Examples
open all close allBasic Examples (1)
NumberQ tests whether an object is explicitly a number:
Scope (3)
The expression must be manifestly a number:
You can test if a quantity represents a number with NumericQ :
On numerical coercion with N , such quantities generally become numbers:
NumberQ [Infinity ] gives False :
The same is true for complex and directed infinities:
NumberQ [Overflow []] and NumberQ [Underflow []] give True :
They are both treated as Real :
Applications (2)
Test if a matrix consists entirely of numbers:
Define a function that only evaluates when the argument is a number:
It does not evaluate with a symbolic argument:
It does evaluate when the argument is a number:
Use FindRoot to find all the solutions of the boundary value problem with :
Plot the solutions:
Tech Notes
Related Guides
History
Introduced in 1988 (1.0) | Updated in 1996 (3.0)
Text
Wolfram Research (1988), NumberQ, Wolfram Language function, https://reference.wolfram.com/language/ref/NumberQ.html (updated 1996).
CMS
Wolfram Language. 1988. "NumberQ." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 1996. https://reference.wolfram.com/language/ref/NumberQ.html.
APA
Wolfram Language. (1988). NumberQ. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/NumberQ.html
BibTeX
@misc{reference.wolfram_2025_numberq, author="Wolfram Research", title="{NumberQ}", year="1996", howpublished="\url{https://reference.wolfram.com/language/ref/NumberQ.html}", note=[Accessed: 04-January-2026]}
BibLaTeX
@online{reference.wolfram_2025_numberq, organization={Wolfram Research}, title={NumberQ}, year={1996}, url={https://reference.wolfram.com/language/ref/NumberQ.html}, note=[Accessed: 04-January-2026]}