Great! Glad you like the app. 🙂 You can show your support by posting a review on the App Store and/or Liking our Facebook page!
Exit Numbers are displayed already in PocketEarth, where such data is available. They appear over the highways in a blue and white text. Our datasource is OpenStreetMap.org a great community driven open mapping project with more than half a million people contributing to it. If you find there are missing Exit numbers, you can help out by adding some of them in your area via the OSM website.