Returns {{{2|1}}} if {{{1}}} is numeric & {{{3|0}}} otherwise.

coderesult
{{Ifnumber|1}}

1

{{Ifnumber|one}}

0

{{Ifnumber|}}

0

{{Ifnumber|1|a number|not a number}}

a number

{{Ifnumber|one|a number|not a number}}

not a number

{{Ifnumber|1000|a number|not a number}}

a number

{{Ifnumber|10.00|a number|not a number}}

a number

{{Ifnumber|1,000|a number|not a number}}

not a number

{{Ifnumber|1,000.50|a number|not a number}}

not a number

{{Ifnumber|99 balloons|a number|not a number}}

not a number

{{Ifnumber|99.9999e10|a number|not a number}}

a number

{{Ifnumber|{{{val|6.B2C}}}|number|value "{{{val|6.B2C}}}" not numeric}}  value "6.B2C" not numeric

This template will not recognize formatted numbers, which is by design since formatted numbers will break expression parsers. To remove the formatting from a number, you can wrap the number first in {{formatnum: number |R}}.

coderesult
{{Ifnumber|1,000.50|a number|not a number}}not a number
{{Ifnumber|{{formatnum:1,000.50|R}}|a number|not a number}}a number