We have extended two perspectives of proportional reasoning to solve problems based in probability. Four future middle grade teachers were enrolled in a mathematics content course that emphasized reasoning about multiplication with quantities. The course expected future teachers to generate and explain methods for solving proportions. Probability had not yet been discussed in the course, which gave insight into how reasoning fostered in the course was invoked in novel tasks. All four future teachers could reason about multiplication with quantities to solve probability problems and could use quantitative methods that accurately reflected how empirical probabilities approach theoretical probabilities as the number of trials increase. [For the complete proceedings, see ED606531.]