Can we install edubuntu tools in elemaentry OS by typing sudo apt-get install ubuntu-edu-secondary ? will the system crash?
You can install the package in question using the command line as it is available in eOS without having to add any additional repos.
So far as crashes, I installed the package on an install of Loki running on a virtual machine and played around with it for a while and had no ill effects with the OS whatsoever. The Potato Guy app was cool! I also screwed around with the Pencil app and a couple others.
Lastly, depending upon your machine and speed of your internet connection, there was a large number of packages downloaded and installed which took some time to accomplish. If you have a slow connection, count on having time for a coffee break!
P.S.-Before I installed the above, I had installed the 'software-properties-common' package as I had to do that before installing elementary Tweaks as well as some other apps. You may need to do so as well.