1-2+3-4+5……..-98+99 =

• ans is 50.
  as 1-2+3-4+5-6+7-....-98+99
  can be written as
  =(1+3+5+7+....+99)-(2+4+6+8+...98)
  =(1+3+5+7+....+99)-2*(1+2+3+..+49)
  =(1+3+5+7+....+99)-2*49*50/2
  (1+3+5+7+....+99)-2450
  =2500-2450 (as it is in AP as 1 1st term 99 last term)
  50 ans
• 12 years agoHelpfull: Yes(43) No(0)
• 1-2+3-4+5-6+......97-98+99
  
  -1+(-1)+(-1)+....+99
  =-49+99=50
• 12 years agoHelpfull: Yes(12) No(0)
• ans 50.
  50*50 - 50*49 = 50 .
• 12 years agoHelpfull: Yes(4) No(0)
• my ans is 50
• 12 years agoHelpfull: Yes(3) No(0)
• ans= 100
  becouse u can break it in two part
  1+3+5........+99
  and -2-4..............-98
  and now apply the A.P. formula and get answer
• 12 years agoHelpfull: Yes(2) No(6)
• 70....
  99-29=70
• 12 years agoHelpfull: Yes(1) No(12)
• ans is 99.
• 12 years agoHelpfull: Yes(0) No(9)
• ans is 50
• 12 years agoHelpfull: Yes(0) No(0)