0.99-0.98-0.97+0.96+0.95-0.94-0.93+...+0.04+0.03-0.02-0.01
0.99-0.98-0.97+0.96=0.01-0.97+0.96=0
0.95-0.94-0.93+0.92=0.01-0.93+0.92=0
……………………
0.01到0.99一共有99项,99÷4=24……3即
﹙0.99-0.98-0.97+0.96﹚+ ﹙0.95-0.94-0.93+0.92﹚...+﹙0.07-0.06-0.05+0.04﹚+0.03-0.02-0.01
=﹙0＋0＋0＋……+0﹚+0.03-0.02-0.01
=（24个）0+0.03-0.02-0.01
=0