I want to analyze (i.e., know the percent alcohol of) a batch of mead.
Its Specific Gravity went from
(the Original Gravity, or "OG")
down to
(the Final Gravity, or "FG").
(If you didn't take an OG reading, you can use the batch planning page to guesstimate it.)
To do the math yourself, you can divide the "drop" (OG minus FG) by 0.00762, or multiply by 131.24, rounding to however may digits you like. Multiplying the drop by 130, or dividing the drop in thousandths (aka "points") by 7, are very common approximations that you might be able to do quickly in your head.