tl;dr

  • Multiplying the middle element of 3x3 matrix with 9 gets thesum of all elements.
  • Adding the least element of 5x4 matrix with the larget and multiplying this result by 10 gets the sum of all elements.
  • multiplying any row with 2000 and subtrating that number by 2 will get you the sum.
  • Remaing two rows can be filled with the result of subtracting 9 from each digit of a corresponding row .