Hi guys how can you follow these small numbers ¹²³?

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http://ubuntuforums.org – a bit puzzled tried to follow these numbers so i can get 0 ++> 9 but keyboard only yields ¹²³ produced with Alt+Gr 123 how can i get 0456789 in the same way tried fonts in Libre Office and so far see none tried google and no answer i am sure one of you clever guys here know the answer thanx in advance shan (Hardware)