Return the time elapsed between 2 times

	A	B
1	=NOW() = 7:44:48 PM
2	=NOW()+0.5 = 7:44:48 AM
3	=MOD(A2-A1, 1) = 12:05:00 AM
4	=MOD(TIME(21, 36, 0)-TIME(3, 0, 0), 1) = 6:36:00 PM