Thanks, but this command doesn't increase the free space.
I try to remove wolfram-alpha and now the free space is about 10%.
Infact, now:
"df -h"
pi@raspberrypi ~ $ df -h
File system Dim. Usati Dispon. Uso% Montato su
/dev/root 3,6G 3,1G 353M 90% /
devtmpfs 103M 0 103M 0% /dev
tmpfs 107M 0 107M 0% /dev/shm
tmpfs 107M 8,5M 98M 8% /run
tmpfs 5,0M 4,0K 5,0M 1% /run/lock
tmpfs 107M 0 107M 0% /sys/fs/cgroup
/dev/mmcblk0p1 56M 21M 36M 37% /boot
tmpfs 22M 0 22M 0% /run/user/106
tmpfs 22M 0 22M 0% /run/user/1000
pi@raspberrypi ~ $is it possible?