Four Fours/20

Puzzle

Using exactly $4$ instances of the number $4$, the task is to write an expression for $20$, using whatever arithmetical operations you consider necessary.

Solutions

Solution $1$

$20 = \paren {4 + \dfrac 4 4} \times 4$

Solution $2$

$20 = 4! - 4 + \paren {4 - 4}$

Solution $3$

$20 = 4 \times 4 + \sqrt {4 \times 4}$

Solution $4$

$20 = \dfrac {4! \times 4} 4 - 4$

Solution $5$

$20 = 4 \times 4 + \sqrt 4 + \sqrt 4$

Also see

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