Please translate this joke into English.

Today, I went to Unicom's business hall to make up the phone bill silently.

Say to your sister, "Add 50!"

My sister looked up and asked, "How much is it?"

I think coldly and silently, when will English be popularized to this extent!

Silently replied in non-standard English: "Find!"

His sister raised her voice: "What's the number?"

In an instant, God, the thunder is rolling! ! ! ! ! ! ! ! ! ! !