To identify the property that Daniela needed to use to avoid her error, we first analyze her work.
Daniela starts with the equation: \[ 13x + 42 = 276 \]
She incorrectly finds that: \[ 13x = 318 \]
The correct step, using the subtraction property of equality, would have been to subtract 42 from both sides: \[ 13x + 42 - 42 = 276 - 42 \] This simplifies to: \[ 13x = 234 \]
The next step, dividing both sides by 13, would then give: \[ x = 18 \]
Since Daniela made a mistake by arriving at 318 instead of 234, she needed to apply the subtraction property of equality correctly to avoid her error.
Therefore, the correct answer is: subtraction property of equality.