Math & Science ⇒ bold italic number

[Kareem]

How to show the number 1 in bold italics math font? I tried using \bm{1} but the looks seems ain't any different from \bf{1}.

[rais]

Numbers are usually set upright in math mode and \bm just switches to bold. Try it like this: \bm{\mathit{1}}

BTW: besides that \bf does not require an argument, it has been deprecated about two decades ago, better use \textbf{..} or {\bfseries ..} instead.

KR
Rainer