1-2 / 1-6 / 1-12 / 1-20 / 1 -. - 2003 times 2004 / 1 is equal to what | Math enthusiast | Mathematical art

1-2 / 1-6 / 1-12 / 1-20 / 1 -. - 2003 times 2004 / 1 is equal to what

1-1/1*2-2-1/2*3-1/3*4-1/4*5-…… 1/2003*2004
=1-(1-1/2)-(1/2-1/3)-(1/3-1/4)-(1/4-1/5)…… -（1/2003-1/2004)
=1-1+1/2-1/2+1/3-1/3…… -1/2003+1/2004
=1/2004