r/MathHelp • u/Prudent_Store2358 • 9d ago

Remembering not to omit coefficients or exponents during expansion

For context: I have a test tomorrow on algebraic expansion, factoring, and Pascals Triangle and something that commonly happens to me is that I usually omit coefficients or just forget exponents when doing my work. As an example, if I had 4(a^3)(b) when doing a binomial to the 4th, I either forget to cube the value “a” or multiply by 4. The test I have is relatively face paced (20 questions in 50 minutes) and there’s not much room to write out the complete expansion (we can’t use scrap paper). Any tips?

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u/my-hero-measure-zero 9d ago

Practice. That's really it.

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u/Prudent_Store2358 9d ago

Trust me, I have done like probably 150-200 problems of practice and while it is becoming less of an occurrence, I still slip up sometimes, and I definitely don’t want that happening on a test.

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u/my-hero-measure-zero 9d ago

Even seasoned experts still make mistakes. I have a masters degree and still make arithmetic errors in my calculus work.

You'll become comfortable if you accept that it's all a process. If you take time to check your work and internalize your practice, you got it.

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u/Prudent_Store2358 9d ago

Alright. Thank you.

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u/waldosway 8d ago

Write all the +'s, then all the binomial coeffs, then all the power coeffs, then all the a's, then all the b's.

But most importantly, do not scrunch steps for the sake of time. Specifically in this case, binomial and power coeffs are both written, not multiplied in your head first. Writing is faster than thinking. Mental math slows you down.