I have previously purchased the full versions of grade 1 to grade 5 apps. What would happen after all the apps are upgraded to the new versions? Can I delete all the other 5 and just use 1 instead?

We are assuming that you have no account created on Splashlearn.com. Once you updated any one app, you can create an account from within the app. This will also help you to access that app's content on the web - with the same account - as your data is synced across all devices. 

As the updates of other apps will be rolled out one by one, you can update the same and link them with the account already created on www.splashmath.com.

After the linking process has been completed for any of the existing SplashLearn apps, you can use any of the updated apps.

However, the linking is only of an email account and not of the profile. As such multiple profiles will be created each time you update an app and link it to your email account. To merge all the multiple profiles of the same child, please email us at help@splashlearn.com with the details and we will link all the grades with a single child account as per your request. We apologize for the inconvenience.