Explaining ?3 × ?3 = +9: The “Removing a Debt” Story

Explaining ?3 × ?3 = +9: The “Removing a Debt” Story

  1. Negative as “Owing” In many real-world contexts, a “negative” amount of money can be thought of as owing money (a debt).
  2. What Does ?3 Represent? ?3 dollars could represent “owing 3 dollars.” In an example, imagine you owe someone $3—that’s ?3.
  3. What Does ?3 Times ?3 Mean? Multiplying by ?3-3 again can be seen as “taking away (or removing) that owing situation 3 times.” Another way to phrase it: A negative sign can be read as “the opposite of.” So ?3 times ?3 is “the opposite of (owing 3 dollars) done three times.”
  4. Result: Owing “Owing $3” Three Times If you “remove” a debt of $3 three separate times, you actually gain $9. This lines up with the arithmetic fact that ?3 × ?3 = +9.


A Quick Breakdown

  1. ?3 = owe $3
  2. Multiplying by ?3 = do the “opposite” of owing $3 three times.
  3. If you’re no longer on the hook for $3 on three different occasions, you come out $9 ahead overall.

That’s exactly what the math statement ?3 × ?3 = +9 captures: “two negatives” (two instances of turning something around) yields a positive result.

Sujoy Kumar Datta

Mentor & coach - GMAT Focus, CAT, SAT Digital, GRE, ACT Math | CAT 99.99 & GMAT Q51 (30 min) | Content & Test creator | 20+ years exp | IIT alum

1 个月

Yes! Perfectly said. A very logical explanation

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