hi,
in fdisk -l command the output is

[root@localhost singh]# fdisk -l

Disk /dev/sda: 320.0 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xecd5ecd5

Device Boot Start End Blocks Id System
/dev/sda1 * 1 6374 51199123+ 7 HPFS/NTFS
/dev/sda2 6375 38912 261361485 f W95 Ext'd (LBA)
/dev/sda5 6375 16573 81923436 7 HPFS/NTFS
/dev/sda6 16574 26772 81923436 7 HPFS/NTFS
/dev/sda7 26773 36971 81923436 7 HPFS/NTFS
/dev/sda8 36972 38912 15591051 83 Linux



now if i want to delete the partition of "/dev/sda5" and again create the partition then it will become "/dev/sda9" . I want that after deleting the partition and again creating it of same size i want to give it the same number i.e if /dev/sda5 is deleted then again creating it how we can get the option to make it /dev/sda5..

If no such command is there then suggest me about it and where i can make change so that it can be made possible.

Delete and re-create it with the same size and device ID?

Why do you want to delete it then? Just modify its partition type to your needs (without deleting), and create the required file system on it.