Equations are composed in another component, Math, independent from Writer. Forget all shortcuts you know in Writer and use the small macro language for equations. Read the manual, at least the provided built-in help.
You can insert subscript in 3 positions:
-
at left as <?> lsub {<?>}
example: A lsub {i}
for i A
-
at bottom as <?> csub {<?>}
example: A csub {i}
-
at right as <?> _ {<?>}
example: A_i
for Ai
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