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1957 AMC 12 Question 24

AMC12 · 1957 AMC 12

Question 24

If the square of a number of two digits is decreased by the square of the number formed by reversing the digits, then the result is not always divisible by:
  1. $9$
  2. the product of the digits
  3. the sum of the digits
  4. the difference of the digits
  5. $11$