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Mensa IQ Coding and Decoding Flashcards

7 cards from real MENSA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. In a certain code, BRIDGE is written as EULGJH. What is the rule being applied?

    Answer: Each letter is shifted forward by 3

    B+3=E, R+3=U, I+3=L, D+3=G, G+3=J, E+3=H — each letter advances 3 positions.

  2. If MOUSE = 13-15-21-19-5, what does 6-15-24 decode to?

    Answer: FOX

    Each number is the position of the letter in the alphabet: F=6, O=15, X=24.

  3. In a code, CAT → DCV and DOG → EPH. Which word encodes to GQX?

    Answer: FQW

    Each letter is shifted +1: C→D, A→B (but shown as C), so first letter +1, second letter+2, third letter+1 — actually C+1=D, A+2=C, T+2=V; D+1=E, O+1=P, G+1=H. Re-examining: CAT→DCV (C+1, A+2, T+2) and DOG→EPH (D+1, O+1, G+1). The pattern for G→H, P→Q, W→X decodes as FPW encoded.

  4. If ★=1, ■=2, ▲=3, ●=4, what is the value of ▲★■●?

    Answer: 3124

    ▲=3, ★=1, ■=2, ●=4, so the sequence reads 3-1-2-4.

  5. COLD is coded as FROG. Using the same rule, how is HEAT coded?

    Answer: KHDW

    C+3=F, O+3=R, L+3=O, D+3=G — shifting each letter by +3: H+3=K, E+3=H, A+3=D, T+3=W.

  6. In a certain number code, 123 means 'eat fresh fruit', 234 means 'fresh juice daily', and 345 means 'daily health boost'. What number stands for 'daily'?

    Answer: 4

    'daily' appears in codes 234 and 345; the common digit is 4.

  7. If PENCIL → QFODKM using a Caesar-type shift, what is RUBBER coded as?

    Answer: SVCCFS

    P+1=Q, E+1=F, N+1=O, C+1=D, I+1=J, L+1=M confirms shift +1; R+1=S, U+1=V, B+1=C, B+1=C, E+1=F, R+1=S.