Small Stakes No-Limit Hold'em

PAGE 17 REGARDING EQUITY:

"

When the combined equity is worth more than what you have

to risk to play on, the situation is profitable."

I am not talkling about obvious extreme hands, but can someone  expound on this idea using some examples and math. maybe i have top two or set on a monotone flop against a solid player who craise shoves the flop….JJ or QQ pf against all in shove…JJ/TT/QQ on a rainbow flop that is 8 high and villain first to act shoves…those kinds of hands or situations. interested in these types of hands you may have played not necessarily these exact hands..i am interesTed in the process for calculating risk and equity. I can't always fold these hands yet i seem to end up on the wrong end a lot.