Wrong Answers Have Fingerprints

You'll learnto read a wrong answer as the fingerprint of one specific mistake, then verify.

The tempting wrong choice is rarely random — it is the output of one specific mistake, and a one-second sanity check catches most of them. This is the whole course in one habit: recognize the trap, then verify before you commit.

8 STEPS · 6 QUICK CHECKS · every wrong answer has a fingerprint · v2

recognize the trap

Before you start

What you're looking at

A preview panel: a right triangle's legs 9 and 12, the tempting answer 21 struck out, and the correct 15.

The question

What specific move produced the tempting wrong answer of 21?

Watch for

Watch 21 decode as 9 + 12, the legs added without squaring, beside the correct 15.

What the symbols mean

Red strikes the wrong answer 21; green marks the correct 15; the card names recognize-then-verify.

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