An amount, say 100,000.00, how to write into words One hundred thousand (currency) only.
Which language do you want? As I know different English used different forms. For example “100011” will be “one hundred thousand eleven” for en_US and “one hundred thousand and eleven” for en_UK. In any case, you will need a macro, IMHO built-in tools still are not good enough.
I want English US
Well - there is a built-in solution now in 6.1 (see release notes).
Since you have used calc tag, then you would need to use the [NatNum12] 0 format string for your cells or cell styles.
That is with Ctrl+1, in Numbers tab. Also check if the Language is the correct.