Having found I had Mathematica 11.0 installed on one Pi and needing to move it 11.3 as on the rest of my cluster I've found apt-get install won't install it, but there is a script at http://www.wolfram.com/raspberry-pi/ which will download the .deb package. However, using dkpg as suggested yields
sudo dpkg -i /tmp/wolfram-engine-install/wolfram-engine_11.3.0+2018052403_armhf.deb
(Reading database ... 146001 files and directories currently installed.)
Preparing to unpack .../wolfram-engine_11.3.0+2018052403_armhf.deb ...
wolfram-eula license has already been accepted
Unpacking wolfram-engine (11.3.0+2018052403) over (11.0.1+2017031701) ...
dpkg: dependency problems prevent configuration of wolfram-engine:
wolfram-engine depends on libhunspell-1.4-0; however: Package libhunspell-1.4-0 is not installed.
wolfram-engine depends on libssl1.0.2; however: Package libssl1.0.2 is not installed.
wolfram-engine depends on coinor-libipopt1v5; however: Package coinor-libipopt1v5 is not installed.
wolfram-engine depends on libraw15; however: Package libraw15 is not installed.
wolfram-engine depends on libexiv2-14; however: Package libexiv2-14 is not installed.
To get over the dependencies I tried
but that failed with
Reading package lists... Done
Building dependency tree
Reading state information... Done Building data structures... Done Building data structures... Done This package is uninstallable Dependency is not satisfiable: libhunspell-1.4-0
Finally, I installed hunspell by hand which reported as its version
@(#) International Ispell Version 3.2.06 (but really Hunspell 1.7.0)
But still Mathematica will not install! Any ideas on how to fix this please? I am running Stretch and I have done all the usual apt-get update .. etc.