QUIZ 4. Four Single Digit Numbers

I've found two answers so far.

  • \(1, 3, 8, 9\)
    • \(10 = 1 + 9\)
    • \(20 = 9 \times 3 - 8 + 1\)
    • \(30 = 3 \times (1 + 9)\)
    • \(40 = 8 \times (9 - 3 - 1)\)
    • \(50 = 3 \times (9 + 8) - 1\)
    • \(60 = 9 \times (8 - 1) - 3\)
    • \(70 = 9 \times 8 - 3 + 1\)
    • \(80 = 8 \times (9 + 1)\)
    • \(90 = 9 \times (8 + 3 - 1)\)
  • \(2, 2, 5, 8\) (Probably the most intuitive answer)
    • \(10 = 2 \times 5\)
    • \(20 = 8 \times 5 \div 2\)
    • \(30 = (8 - 2) \times 5\)
    • \(40 = 8 \times 5\)
    • \(50 = 5 \times (8 + 2)\)
    • \(60 = 5 \times 2 \times (8 - 2)\)
    • \(70 = 5 \times (8 \times 2 - 2)\)
    • \(80 = 5 \times 8 \times 2\)
    • \(90 = 5 \times (8 \times 2 + 2)\)

I haven't bruteforced this yet so there may be other answers.


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