10-99 has 2*90= 180 numbers;

100- 199 has 3* 100=300 numbers;

200-299 has a number of 3* 100=300;

300-359 has 3*60= 180 numbers.

At this time, a * * * uses the number 9+180+300+180 = 969;

98 1-969= 12,

So count backwards to four, which is 350,361,362,363.

So Xiaoming's diary has 363 pages.