Bob's your uncle

...And Bob's your uncle is an expression commonly used in Great Britain and Commonwealth countries. Typically, someone says it to conclude a set of simple instructions, similar to the French expression "et voilà !".

"Bob's your uncle" is an exclamation that is used when "everything is all right" and the simple means of obtaining the successful result is explained. For example: "left over right; right over left, and Bob's your uncle – a reef knot". Sometimes the phrase is followed with "and Nellie's your aunt" or "and Fanny's your aunt". It is sometimes elaborately phrased Robert is your mother's brother or similar for comic effect.

It is suggested that the expression arose after Conservative Prime Minister Robert "Bob" Cecil appointed his nephew, Arthur Balfour, as Chief Secretary for Ireland in 1887; apparently surprising and unpopular. In this sense the expression also carried a hint of sarcastic envy or resentment, rather like "it's who you know"; not "what you know" that gets results, or "easy when you know how". Since then the meaning has become acknowledging, announcing or explaining a result or outcome that is achieved more easily than might be imagined