MENTAL MULTIPLICATION MARATHON - 20-Digit by 20-Digit Multiplication

(There can be more than one attempt at this category with different sets of questions each time if time permits.)

Duration: 10 Minutes

Software:MEMORIAD™ Multiplication Software

Calculation Stage

  1. A question of random two 20-digit numbers to be multiplied is generated by MEMORIAD™ Competition Software.
  2. All the numbers are chosen randomly and each number must be a twenty-digit number (so there will not be any number whose first digit is zero).
  3. The answer must be the product of the two numbers given.
  4. As the competitors make the mental multiplication, they can write the last result of the multiplication from right to left or from left to right in order. However, while the multiplication is carried out in mind, any clue information cannot be written anywhere.
  5. Even though a competitor is free to use the full 10 minutes for his/her calculation stage, using less time is important if the answer is correct. If the answer is correct, the one who used the shortest time is the winner.
  6. If the competitor is confident about his/her calculations, he must stop the calculation stage to fix the calculation timer. As soon as he stops the calculation stage, software closes the calculation stage and shows the calculation result and score of that competitor on his screen (*).
  7. The competitor has three minutes to check his/her answers and mistakes when his/her calculation stage ends. Beyond that time software closes the result screen automatically.
  8. After completing the task, the competitor must wait silently until other competitors complete their tasks.
  9. If the answer is not correct, no matter how much time the competitor used for his calculation, his calculation time is considered 10 full minutes.
  10. When the full time is over, the software automatically ends the calculation stages of those who have not finished their calculation stages yet and shows their calculation results to them on their screens. The competitors have three minutes to check their answers and mistakes. Beyond that time software closes the result screen automatically (*).

(*) Memoriad™ Committee may decide to announce the all results after the end of the calculation stage for all competitors.


  1. There are no points given for this calculation. The time used for the calculation counts.
  2. It does not matter how many wrong or correct digits are present if the answer is wrong.
  3. If the competitor completes his/her answers by using less time than the time given, then the time used is recorded by the software when he/she finishes the calculation stage.
  4. In this category there can be more than one attempt. If more than one attempt are made, the best score obtained from all attempts counts.
  5. In case of any tie, the second best scores that are not equal decide the winner.