You can make 189 valid words from the letters in AIORSTU using the Scrabble US/CAN dictionary.
How many points is AIORSTU worth in Scrabble?
AIORSTU is worth 7 points in Scrabble (US/CAN) and 8 points in Words With Friends.
How do I use the Word Unscrambler tool?
Enter any letters into the input box and press Search. The tool will return every valid English word that can be made from those letters using the dictionary you select.