4 Numbers

$\begin{aligned} \text{Numbers: }&1,\ 9,\ 21,\ 32\\ \text{Operations: }&+,\ -,\ \times,\ \div,\ (\ ) \end{aligned}$

Using all 4 of the above numbers, any of the 4 operations, and any number of parentheses, can you write an expression that equals 24?

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Details and Assumptions:

• Each number has to be used exactly once.
• Each operation can be used as many times as desired.
• No other operations are allowed: in particular, concatenation, square roots, factorials, etc.