Comment 1 for bug 1754340

I can't reproduce this. Can you please fully update your system and try again? If that doesn't help, please post the full output of `apt show speedcrunch libqt5core5a`.

That library -- libdouble-conversion.so.1 -- is a dependency of libqt5core5a so it should be installed as a dependency; I'm thinking you either tried at a bad time when some things were broken (18.04 is a while from release) or your system is hosed in some fashion (again, it's a dev version: that can happen).