How do I stop pages,numbers and keynote trying to reinstall on my ipad?

[adriancal]

I uninstalled pages,keynote and numbers from a
16Gb ipad air to save some space but they keep trying
to reinstall themselves and I now have three
greyed out icons for those apps.
The apps themselves don't run but look like placeholder
icons. given that the ipad only has 16gb storage
I am trying to minimise the installed applications
as much as possible.

Any tips?