I want to multiply a constant from a macro with a deimension using `dimexpr`

.

When using real numbers the decimal point and the decimal digits are typeset behind the result and the result is a mutliplication with the floor value of the constant used.

```
\documentclass{report}
\begin{document}
\def\const{1.9}
\noindent
\the\dimexpr \linewidth*\const\relax \newline
\the\dimexpr \linewidth*\numexpr\const\relax\relax \newline
\the\linewidth
\end{document}
```

The second multiplication is an attempt to use the suggestion from here, to wrap the macro in a sub expression

## Best Answer

`\dimexpr`

doesn't allow arbitrary calculations: you need to have things in the correct form. In particular, if you want to multiply a dimension by a decimal then you need to use the formSo you example will work with

while the format

can only be used if

`\const`

is an integer.(The linked answer Multiplication with dimexpr? does mention this limitation.)