1) Yes, I installed one the other day that is a calculator, but.. it's ON MY PHONE. 2) I use it every week, but I just use it in my browser. Key note: pretty sure installing the app doesn't increase your video conferencing capacity. 3) Bandwidth is the useable range of frequency space available in a comm. channel; usually defined mathematically as the upper and lower frequencies whose magnitude is -3 dB less than the highest magnitude, or center frequency.