Four Fours/64/Solutions/1

Puzzle: Four Fours: $64$

Using exactly $4$ instances of the number $4$, the task is to write an expression for $64$, using whatever arithmetical operations you consider necessary.

Solution

$64 = \paren {4 + 4} \times \paren {4 + 4}$

Sources

• 1968: Henry Ernest Dudeney: 536 Puzzles & Curious Problems ... (previous) ... (next): Answers: $109$. The Two Fours