I have a question about numerals in Spanish. I'm supposed to rewrite various sentences with numerals in them, but I have a slight problem. How do you say 200th, 300th, 400th etc in Spanish? My morphology textbook tells me that 'ducentésimo, tricentésimo...' is not used anymore, so I was wondering if there is any other way? And if there is, how would it work with numbers like 450th, 818th etc?
Also, is there any way to express the multiples? Like 6x, 8x etc? Again, my morphology textbook says that only 'doble, triple, cuadruple' is used, so how would I say eg. 'seven times'?