9+99+999+9999+............+999999.......23times. Find the last three digits

• last three digit will be 087 ...
  1. for unit place-> 9+9+..23 times = 23*9=207 (unit place is 7) (20 will be added to tenth place)
  
  2. for tenth place-> 9+9+9..22 times =22*9=198(+20)=>218(tenth place is 8)(21 will be added to hundred place)
  
  3. for hundred place-> 9+9+9..21 times=21*9=189(+21)=>210(hundred place is 0)
• 11 years agoHelpfull: Yes(93) No(2)
• 9(1+11+111+.......+111...23times)
  23times.....1111
  +22times.....111
  +21times......11
  + .
  .
  1
  --------------------
  23
  + 22
  + 21
  -----------------
  343
  343*9=087
  ans:=087
• 11 years agoHelpfull: Yes(12) No(1)
• 087
  9(1 +11+111+................23 times)
  9(last digit=3
  2nd last digit=last digit of(22+2)=4
  3rd last digit=21+2=3;)
  9(343)=.............087
  
• 11 years agoHelpfull: Yes(6) No(0)
• it can be rewrite as (10-1)+(100-1)+......23 times
  -->(10+100+1000....23terms)-23
  sum of the GP above =1111-23 = 1088 so the last three digits are "088"
• 11 years agoHelpfull: Yes(2) No(8)
• at the units place 9 appears 23 times so 9*23=227,now after addition 9 comes at the units place and 22 as carry,now at tens place 9 appears for 22 times so 9*22=198,now 198+22(previos carry)=220 so 0 comes at tens place nd 22 as carry,now 9 appears for 21 times s0 9*21=189+(22)=211 so finally last three digits are 109.....
  
• 11 years agoHelpfull: Yes(0) No(4)
• ans is 987
• 11 years agoHelpfull: Yes(0) No(7)
• there is 23 times then write 23 times one and then a zero.so,
  111111111111111111111110-24=11111111111111111111186
• 11 years agoHelpfull: Yes(0) No(4)
• 087 will be the last three digits.
• 11 years agoHelpfull: Yes(0) No(0)
• 23*9=207=>unit place is 7 and 20 will be added to tenth place
  22*9=198+20=218=>unit place is 8 and 21 will be added to hundredth place
  21*9=189+21=210=>unit place is 0
  so,answer is 087
• 8 years agoHelpfull: Yes(0) No(0)