Final answer:
The error made in the given expression is the incorrect use of addition and subtraction operations. The correct result of the given expression is 81.
Step-by-step explanation:
The error made in the given expression is the incorrect use of addition and subtraction operations.
The correct order of operations to follow is PEMDAS (Parentheses, Exponents, Multiplication and Division from left to right, and Addition and Subtraction from left to right).
Therefore, the given expression should be evaluated as follows:
- 85 - 7 + 13 - 10
- 78 + 13 - 10
- 91 - 10
- 81
Hence, the correct result of the given expression is 81.
The mistake in the expression arises from an error in the order of operations. By correctly applying the PEMDAS rule (Parentheses, Exponents, Multiplication and Division from left to right, and Addition and Subtraction from left to right), the expression should be evaluated as:
85 - 7 + 13 - 10 - (78 + 13) - (91 - 108) - 1
Simplifying each operation step by step leads to the correct result of 81. This highlights the importance of following the established order of operations to obtain accurate solutions in mathematical expressions.