#### Answer

$4^2-5\times(2+1)$

#### Work Step by Step

The order of operations states that first we perform operations inside grouping symbols, such as parentheses, brackets, and fraction bars. Then, we simplify powers. Then, we multiply and divide from left to right. Finally, we add and subtract from left to right.
When we put parentheses around $2+1$, the order of operations requires that we add these terms first.
This leaves us with $4^2-5\times3$
Following the order of operations, we would then simplify powers: $16-5\times3$
Then we would multiply: $16-15$
And finally, we would subtract: $1$. This makes the equation true.