It will depend on the situation. In your examples: "The answer is on page": "one thirty five" or "one hundred and thirty five" both sound good and are quite common. If you were talking about money you may need to be more specific in some cases. If you were at a currency exchange and you said you wanted to change "one thirty five" the person may not know if you mean $1.35 or $135 A lot of the time it will be obvious though. You: "How much for this apple?" Shop Keeper: "One thirty five" you can guess it's $1.35 as $135 would not make be right for an apple. You: "How much are these shoes?" Shop Keeper: "One thirty five" You would assume the person is saying that the shoes are $135.. Hope this helps :)