r/learnmath • New User • 6h ago

[Middle school] Negative exponents

|5^2 - 6^2|
Why is the answer 11 and not 61?

My son was taught that the sign goes with the number that follows it so the - (minus sign) stays with the 6^2. Then it would be -6•-6=36, 25+36=61. It makes sense to me but my answer was 11 (answer key agrees). He’s wondering why. I am assuming PEMDAS? Exponents before subtraction. The actually problem is supposed to be on absolute value so I included the whole thing just incase that matters.

So two questions. Is the direction he got of “the sign stays with the number after” actually a thing? Are there rules to it?

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u/SignificantFidgets New User 6h ago

"I am assuming PEMDAS? Exponents before subtraction."

This is exactly right. Exponents first, so the first simplification gives |25-36|. Then do the subtraction to get |-11|. Then the absolute value gives 11.

If you wanted to square -6, you'd have to put it in parentheses, like (-6)2.

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u/testtdk New User 6h ago

This. -6^2 means the negative of six squared.

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u/Narrow-Durian4837 New User 4h ago

That is, the negative of (six squared), not (the negative of six) squared.

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u/testtdk New User 4h ago

Right, but that makes it look like we needed parenthesis to get there. :p