Stone, C.W.; '08 Arithmetical Abilities and Some Factors Determining Them. Teachers College Contributions to Education, No. 19. Suzzallo, H.; '11 The Teaching of Primary Arithmetic. Thorndike, E.L.; '00 Mental Fatigue. Psychological Review, vol. 7, pp. 466-482 and 547-579. Thorndike, E.L.; '08 The Effect of Practice in the Case of a Purely Intellectual Function. American Journal of Psychology, vol. 10, pp. 374-384. Thorndike, E.L.; '10 Practice in the case of Addition. American Journal of Psychology, vol. 21, pp. 483-486. Thorndike, E.L., and Donovan, M.E.; '13 Improvement in a Practice Experiment under School Conditions. American Journal of Psychology, vol. 24, pp. 426-428. Thorndike, E.L., and Donovan, M.E., and Hahn, H.H.; '14 Some Results of Practice in Addition under School Conditions. Journal of Educational Psychology, vol. 5, No. 2, pp. 65-84. Thorndike, E.L.; '15 The Relation between Initial Ability and Improvement in a Substitution Test. School and Society, vol. 12, p. 429. Thorndike, E.L.; '16 Notes on Practice, Improvability and the Curve of Work. American Journal of Psychology, vol 27, pp. 550-565. Walsh, J.H.; '06 Grammar School Arithmetic. Wells, F.L.; '12 The Relation of Practice to Individual Differences. American Journal of Psychology, vol. 23, pp. 75-88. White, E. E.; '83 A New Elementary Arithmetic. Whitley, M. T.; '11 An Empirical Study of Certain Tests for Individual Differences. Archives of Psychology, No. 19. Wiederkehr, G.; '07 Statistiche Untersuchungen über die Art und den Grad des Interesses bei Kindern der Volksschule. Neue Bahnen, vol. 19, pp. 241-251, 289-299. Wilson, G. M.; '19 A Survey of the Social and Business Usage of Arithmetic. Teachers College Contributions to Education, No. 100. Wilson, G. M., and Hoke, K. J.; '20 How to Measure. Woody, C.; '10 Measurements of Some Achievements in Arithmetic. Teachers College Contributions to Education, No. 80. INDEX Abilities, arithmetical, nature of, 1 ff.; measurement of, 27 ff.; constitution of, 51 ff.; organization of, 137 ff. Abstract numbers, 85 ff. Abstraction, 169 ff. Accuracy, in relation to speed, 31; in fundamental operations, 102 ff. Addition, measurement of, 27 ff., 34; constitution of, 52 f.; habit in relation to, 71 f.; in the higher decades, 75 f.; accuracy in, 108 f.; amount of practice in, 122 ff.; interest in 196 f. Aims of the teaching of arithmetic, 23 f. AMES, A. F., 89 Analysis, learning by, 169 ff.; systematic and opportunistic stimuli to, 178 f.; gradual progress in, 180 ff. Area, 257 f., 275 Arithmetic, sociology of, 24 ff. Arithmetical abilities. _See_ Abilities. Arithmetical language, 8 f., 19, 89 ff., 94 ff.