Question

Difficulty: MediumOrder of Operations

An important part of algebraic evaluation is applying operations in the correct sequence. Consider the mathematical expression provided below:

−32+4×[15÷(2−5)]−(−6) -3^2 + 4 \times [15 \div (2 - 5)] - (-6)

What is the final calculated value of this expression?

Answer: -23

Answer

-23
Following the strict order of operations, we first resolve the grouping symbols from the inside out to get −5-5 for the bracketed term. Next, we evaluate the isolated exponent −32-3^2 as −9-9. Then, we multiply the 44 by our bracketed result of −5-5 to get −20-20. Finally, we perform addition and subtraction from left to right: −9+(−20)+6-9 + (-20) + 6, which results in −23-23.

Step-by-Step Solution

1
Evaluate innermost parentheses
(2−5)=−3(2 - 5) = -3
Order of operations dictates solving expressions inside the innermost grouping symbols first.
2
Evaluate brackets
[15÷(−3)]=−5[15 \div (-3)] = -5
Continue evaluating operations inside the next level of grouping symbols.
3
Evaluate exponent
−32=−9-3^2 = -9
Exponents are evaluated before multiplication and division. The negative sign is outside the base, so only the 3 is squared.
4
Perform multiplication
4×(−5)=−204 \times (-5) = -20
Multiplication and division are performed from left to right before any addition or subtraction.
5
Perform addition and subtraction
−9+(−20)−(−6)=−23-9 + (-20) - (-6) = -23
Add and subtract from left to right. Subtracting a negative number is mathematically equivalent to adding a positive number.

Key Concept

Applying the order of operations (PEMDAS) to expressions with nested grouping symbols, exponents, and signed numbers.
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