Four Fours/4/Solutions/3

Puzzle: Four Fours: $4$

Using exactly $4$ instances of the number $4$, the task is to write an expression for $4$, using whatever arithmetical operations you consider necessary.

Solution

$4 = \sqrt {\dfrac 4 {.\dot 4} } + \dfrac 4 4$

where $.\dot 4$ is interpreted as $0.44444 \ldots = \dfrac 4 9$

Sources

• 1980: Angela Dunn: Mathematical Bafflers (revised ed.) ... (previous) ... (next): $1$. Say it with Letters: Algebraic Amusements: Four Fours