For n≥10, n! is divisible by 10, so (n!)2 is divisible by 100. Therefore, only the terms (1!)2,(2!)2,…,(9!)2 contribute to the last two digits.
Compute each term:
(1!)2=12=1
(2!)2=22=4
(3!)2=62=36
(4!)2=242=576
(5!)2=1202=14400
(6!)2=7202=518400
(7!)2=50402=25401600
(8!)2=403202=1625702400
(9!)2=3628802=131681894400
Now, take the last two digits of each term:
(1!)2=1 (last two digits: 01)
(2!)2=4 (last two digits: 04)
(3!)2=36 (last two digits: 36)
(4!)2=576 (last two digits: 76)
(5!)2=14400 (last two digits: 00)
(6!)2=518400 (last two digits: 00)
(7!)2=25401600 (last two digits: 00)
(8!)2=1625702400 (last two digits: 00)
(9!)2=131681894400 (last two digits: 00)
Sum the last two digits:
01+04+36+76+00+00+00+00+00=117
The last two digits of 117 are 17.
Answer: 17