Can I replace iPhone with iPad 3G

I like the iPhone it is convenient. I have an iPhone 4
I don't call anyone except my wife really. Mostly I use Facebook, Instagram, the camera, I use to like the maps but that changed. I check lots of email from work. And txt... Again mostly my wife.

So it's fair to say I like it. But doing anything like web browsing on it is annoying. The screen is too small for most things games, movies, signing up to Mac forums. . And the AT&T grandfathered unlimited plan has risen over the years to almost 200 a month. I could have a really reasonably priced car for that. Or better healthcare.

iPad. Never got the point of a big iPhone until I bought one for ....yea, her. I got the iPad Mini. So far I love it and it fits in my hand better than the Maxi IPad. If this thing had 3G (it doesn't ...maybe when I buy one for myself) would I be able to do all the things I do on the iPhone? Facebook,Instagram, email, and txt (txt pictures as well) from the iPad 3G?

Could I then replace my iPhone with a basic cell phone? What functionality would I loose by not having an iPhone to go with the iPad. I.e. I notice you can receive txt on the iPad with wifi. Is that dependent on my number being associated with an iPhone? Anything I should know?

It's up to you of course, but yes, an iPad with cellular capability (4G LTE) can basically do everything the iPhone can do except make and receive phone calls. I own an iPad 3 with 4G LTE (Verizon) and use it for those things you stated above. I have an ordinary cell phone with T-Mobile which I use.