science-mathematics: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/science-mathematics - from package: science-mathematics

You may install the required package with command apt-get install {package}

Error in other languages:
science-mathematics: bevel nie gevind nie
science-mathematics: comandă negăsită
science-mathematics: comando não encontrado
science-mathematics: commande introuvable
science-mathematics: command not found
science-mathematics: käsku ei ole
science-mathematics: không tìm thấy lệnh
science-mathematics: komanda nerasta
science-mathematics: Kommando nicht gefunden.
science-mathematics: kommandot finns inte
science-mathematics: komut yok
science-mathematics: nie znaleziono polecenia
science-mathematics: níor aimsíodh an t-ordú
science-mathematics: no se encontró la orden
science-mathematics: no s'ha trobat l'ordre
science-mathematics: opdracht niet gevonden
science-mathematics: parancs nem található
science-mathematics: perintah tidak ditemukan
science-mathematics: príkaz nenájdený
science-mathematics: příkaz nenalezen
science-mathematics: команда не найдена
science-mathematics: командата не е открита
science-mathematics: 命令找不到
science-mathematics: コマンドが見つかりません