Add other arithmetic tips

1 job for modifH21 in 25 seconds (queued for 15 minutes and 10 seconds)
Status Job ID Name Coverage
  Build
failed #1028756
build
beamer-build

00:00:25

 
Name Stage Failure
failed
beamer-build Build
                                                  
l.219 \end{frame}

! ==> Fatal error occurred, no output PDF file produced!
Transcript written on main.log.
make: *** [makefile:2: all] Error 1
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1