Answer
1
Work Step by Step
The error is in the final step, which is the addition of a positive number and a negative number: $-4+5$
To add numbers with opposite signs, you find the difference of their absolute values and assign the sum the sign of the addend with the largest absolute value.
$|5|\overset?\gt|-4|$
$5\gt4$
Subtract 4 from 5. Since the positive number, 5, has the largest absolute value, the sum will be positive.
$5-4=1$
