Quandaries and Queries
  

 

Who is asking: Student
Level: Secondary

Question:
What is the sum of the digits in the decimal form of 21999 * 52002?

example: 32 * 43 =
9 * 64 =
576 =
5+7+6 =
18
 

 

Hi Kelsey,

21999 52002 = 21999 51999 53
= (2 5)1999 53.
The result is a 2002 digit number, but you can find out the sum of the digits without that much calculations.

Claude

  
 

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