What is Computation?

Legal Definition
Computation is any type of calculation that follows a well-defined model understood and expressed as, for example, an algorithm.

The study of computation is paramount to the discipline of computer science.
-- Wikipedia
Legal Definition
Counting, calculation. It is a reckoning or ascertaining the number of any thing.

2. It is sometimes used in the common law for the true reckoning or account of time. Time is computed in two ways; first, naturally, counting years, days and hours; and secondly, civilly, that is, that when the last part of the time has once commenced, it is considered as accomplished. Savig. Dr. Rom. 182. See Infant; Fraction. For the computation of a year, see Com. Dig. Ann; of a mouth, Com. Dig. Temps. A; 1 John. Cas. 100 15 John. R. 120; 2 Mass. 170, n.; 4 Mass. 460; 4 Dall. 144; 3 S. & R. 169; of a day, vide Day.; and 3, Burr 1434; 11 Mass. 204; 2 Browne, 18; Dig. 3, 4, 5; Salk. 625; 3 Wils. 274.

3. It is a general rule that when an act is to be done within a certain time, one day is to be taken inclusively, and one exclusively. Vide Lofft, 276; Dougl. 463; 2 Chit. Pr. 69; 3 Id. 108, 9; 3 T. R. 623; 2 Campb. R. 294; 4 Man. and Ryl. 300, n. (b) 5 Bingh. R. 339; S. C. 15, E. C. L. R. 462; 3 East, R. 407; Hob. 139; 4 Moore, R. 465; Har. Dig. Time, computation of; 3 T. R. 623; 5 T. R. 283; 2 Marsh. R. 41; 22 E. C. L. R. 270; 13 , E, C. L. R. 238; 24 E. C. L. R. 53; 4 Wasb. C. C. R. 232; 1 Ma-son, 176; 1 Pet. 60; 4 Pet. 349; 9 Cranch, 104; 9 Wheat. 581. Vide Day; Hour; Month; Year.
-- Bouviers Law Dictionary
Legal Definition
The act of computing, numbering, reckoning or estimating. The account or estimation of time by rule of law, as distinguished from any arbitrary construction of the parties. Cowell.
-- Black's Law Dictionary