Pushbullet lets you send texts from your Android tablet.

Pushbullet has posted another update today that makes it possible to send and reply to SMSs on Android tablets. For this to work, SMS Sync must be enabled in Pushbullet on the phone. Launch Pushbullet on the tablet and tap SMS and your SMS threads will be displayed. Tap a SMS to open the conversation history and start typing and send your messages. Recipients won't know you're sending the SMS from a tablet. The app will sync your SMSs to your phone and the latter will then send the SMS. Pushbullet supports multiple phones. Simply select the phone you want to send from a selector within the app. 

This new feature is currently free, but, starting December 1st, unlimited texting will be available to Pro users only, while free accounts will be limited to 100 SMSs per month. Download the update Google Play and enjoy sending/receiving SMS on your tablet.