“Two negatives make a positive” is easy to memorise and easy to misuse. It applies to multiplying two negative numbers, not to every expression containing two minus signs. Understanding the pattern makes the rule less mysterious.
Follow a sequence through zero
Keep the first factor at negative three and let the second factor decrease by one each time. The products begin: negative three times three is negative nine; times two is negative six; times one is negative three; times zero is zero.
Each step increases the product by three. Continuing the same pattern, negative three times negative one gives positive three, and negative three times negative two gives positive six. The sign rule preserves the relationship already visible before crossing zero.
Check it with the distributive law
Since two plus negative two equals zero, negative three multiplied by that sum must equal zero. Distributing gives negative six plus the product of negative three and negative two. For the total to remain zero, the second product must be positive six.
This argument connects the rule to familiar arithmetic rather than inventing a separate exception for negative numbers. Write the brackets carefully so it is clear which quantities are being multiplied.
Keep addition separate
Negative three plus negative two is negative five. There is no multiplication in that expression, so the multiplication sign rule does not apply. Ask a learner to name the operation before deciding the sign.
For practice, compare three expressions: negative four times negative two, negative four plus negative two, and negative four minus negative two. Explain each result in words, then check it with a pattern or number line where appropriate.
If an answer is wrong, first locate the operation that was misunderstood. Repeating the slogan more loudly rarely helps. A short explanation of why the rule fits the rest of arithmetic gives the learner something they can reconstruct when memory fails.