1(1!)+2(2!)+-------+2012(2012!)=?

• ans is 2013!-1
  1(1!)=1
  1(1!)+2(2!)=1+4=5 ( 5 can b wrtten as 3!-1)
  1(1!)+2(2!)+3(3!)= 4!-1
  .
  .
  1(1!)+2(2!)+-------+2012(2012!)= 2013!-1
  
• 11 years agoHelpfull: Yes(63) No(2)
• 
  1(1!)+2(2!)=(3!)-1=5
  1(1!)+2(2!)+3(3!)=4!-1=23
  ................
  1(1!)+2(2!)+-------+2012(2012!)=(2013!)-1(ans)
  
  
• 11 years agoHelpfull: Yes(6) No(1)
• 1(1!)+2(2!)=5=3!-1
  
  so 1(1!)+2(2!)+-------+2012(2012!)=2013!-1
• 11 years agoHelpfull: Yes(1) No(2)
• 1(1!)+2(2!)=(3!)-1=5
  1(1!)+2(2!)+3(3!)=4!-1=23
  ................
  1(1!)+2(2!)+-------+2012(2012!)=(2013!)-1
• 11 years agoHelpfull: Yes(1) No(0)
• 1(1!)+2(2!)=1+4=5 so
  5 can be split as 3!-1
  1(1!)+2(2!)+3(3!)=1+4+18=23
  3!+1!=4!=24
  3-2=1=1
  24-1=23
  similiarly 1(1!)+2(2!)+.....+2012(2012!)can be written as
  2012!+1!=2013!
  2012-2011=1
  so answer is 2013!-1!
• 11 years agoHelpfull: Yes(1) No(0)
• 1(1!) can be written as 2!-1!
  2(2!) can be written as 3!-2!
  .
  .
  .
  on adding all,we get directly 2013!-1!.
• 11 years agoHelpfull: Yes(1) No(1)
• 2013!-1
  consider 1(1!)+2(2!)+3(3!)+4(4!)=119 which is 5!-1
  similarly 2013!-1
• 11 years agoHelpfull: Yes(0) No(2)