# Confusion b/w notations

I was helping my cousin with his hw when i came aacross this problem... I can easily differentiate b/w 3.5 ( three point five) and 3.5 ( three dot product five) when they come in different situations.. but there was this equation written which had the term 3.5. I interpreted it as decimal notation whereas it was for dot product multiplication... My question is that is there any different way of coming t know which notation is meant for which??