The way I learned to use it was it was like Pac-Man, you would point the mouth to the one with the most because Pac-Man always wanted to eat the most. Was really stupid at the time but also really helps.
My psych prof just showed us a study done where people who've never gotten into college have a harder time switching into formal operational thought. Most times people who've dropped out of hs have great thought into what they're interested in, and anything else is concrete operational thought.
Well somebody failed math