bc: 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 CentOS possible default full paths are:

/usr/bin/bc - from package: bc

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/bc - from package: bc
/usr/lib/plan9/bin/bc - from package: 9base

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

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