From type/Numeric

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multi sub    log10(Numeric:D  --> Numeric:D)
multi method log10(Numeric:D: --> Numeric:D)

Calculates the logarithm to base 10. Returns NaN for negative arguments and -Inf for 0.

From type/Cool

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multi method log10()
multi sub log10(Numeric $x)
multi sub log10(Cool    $x)

Coerces the invocant (or in the sub form, the argument) to Numeric (or uses it directly if it's already in that form), and returns its Logarithm in base 10, that is, a number that approximately produces the original number when 10 is raised to its power. Returns NaN for negative arguments and -Inf for 0.

say log10(1001);            # OUTPUT: «3.00043407747932␤»