Probability of an event happening = ____

$\mathrm{Probability} = \frac{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{Outcomes} }{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{Possibilities}}$

$\mathrm{Probability} = \frac{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{possibilities} }{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{Impossibilities}}$

$\mathrm{Probability} = \frac{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{possibilities} }{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{Outcomes}}$

$\mathrm{Probability} = \frac{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{Likely} \mathrm{outcomes} }{\mathrm{Total} \mathrm{number} \mathrm{of} \mathrm{Unlikely} \mathrm{outcomes}}$