tried to explain why +8 teasers are not good odds to my buddy

[l7ustin]

but he would not listen. can one of the math guys explain. he likes to bet the 3 team +8 teasers on basketball games on bookmaker for -120. he does ok but i have noticed that most of the time his wins win ATS without the 8 and about 50/50 when he losses ATS he losses with the 8 point cushion as well...maybe there is already a thread about this if so could someone link it??

thanks all