Răspuns:
Explicație pas cu pas:
1/2*3 = 1/2 - 1/3
1/3*4 = 1/3 - 1/4
.........
1/999*1000 = 1/999 - 1/1000
prima paranteza devine
1/2 - 1/3 + 1/3 - 1/4 .......+1/999 - 1/1000 = 1/2 - 1/1000 = 500/1000 - 1/1000
= 499/1000
a doua paranteza
1/999 - 1/999 + 1/1000 = 1/1000
____________
499/1000 : 1/1000 = 499/1000*1000 = 499