As stated, a negative number means the bookie sees the outcome as more likely. The number gives you how much you would need to bet to winR$100 in profit. A positive number indicates the underdog. The number shown in the betting odds tells you how much you would win if you betR$100.
A plus (+) represents longer odds, in which case you'll win more for your wager, while a minus (-) means you're betting on a more likely outcome (as deemed by the sportsbook) and will win less when you emerge victorious. For example,R$100 on +110 odds wins youR$110, whileR$110 on -110 odds wins youR$100.