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TL;DR

Difference of Squares Mental Trick: A canonical quantitative trading interview question at foundation difficulty. Commonly asked at Optiver, SIG, Akuna Capital, IMC, Flow Traders.

By Valenke Exam Prep Team·Last updated 2026-06-01
foundationRapid Arithmetic

Difference of Squares Mental Trick

Asked at: Optiver, SIG, Akuna Capital, IMC, Flow Traders

Problem
Compute these mentally, each within 5 seconds: 1. 47×5347 \times 53 2. 86×7486 \times 74 3. 123×117123 \times 117 4. 998×1002998 \times 1002

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