Complex sentence: To test for divisibility by 5, double the unit digit and subtract this from the remaining number, if the result is divisible by 5 then the given number is divisible by 5.
Split into simpler sentences: To test for divisibility by 5, double the units digit and subtract the result from the number formed by the rest of the digits. If the result is divisible by 5 then the given number is divisible by 5.