Updates for apps not working

ive got an iPhone 4s. Tons of apps installed

Yesterday I had an update for an app. A red 1 appearing on the App Store icon. Went to update the app and instead it opened the app instead of updating it !

Now I've got 3 updates. I go to update the app and same thing. Friends on a forum I post on are having the same issue

How come I can't update my apps ?? Never had this before.