How does an ip address allow your computer to be reached

Not sure if this helps

The "IP" part of IP address stands for "Internet Protocol." The "address" part refers to a unique number that gets linked to all online activity you do...somewhat like a return address on a letter you'd send out. (All this happens in milliseconds.)
Your computer is hooked up to the Internet, one way or the other. When you go online for email, to shop or chat, your request has to be sent out to the right destination, and the responses and information you want need to come back directly to you.

An IP address plays a significant role in that.

You and your computer actually connect to the Internet indirectly: You first connect to a network that is 1) connected to the Internet itself and 

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