What you're seeing is considered 'American Style Betting Odds'
Here in North American, most places will display odds in 'American Odds'. Here is an example of what they look like:
Saturday's Hockey Game:
Ottawa Senators (-120)
Montreal Canadiens (+140)
The numbers in the brackets represent the odds. American Odds have 2 pieces of info; 1 is the (+/-) and 2 is the number that follows.
The (+/-) in front of the number shows what placing a bet on that outcome will pay out.If negative (-), that means the outcome is likely to occur and betting on that pays out less than you wagered. But a positive (+) means the outcome is less likely to occur and betting on that pays out more than you wagered.
What does this all look like?
Using the example above, -120 means you need to wager $120 to win $100. Therefore your pay out would be $220 back, which is your original bet of $100, and then your profit of $120.
The 'T5.5', means for NHL betting anyways; TOTAL SCORE. So the combined score of the game will be at least 5.5
Now this is generally also showing with OVER/UNDER odds. Which when used as 'likely hood' as in the example above, you can take the OVER or UNDER on the TOTAL SCORE, which is also known as the LINE in football.