This programed mathematics textbook (Volume I) is for student use in vocational education courses. It was developed as part of a programed series covering 21 mathematical competencies which were identified by university researchers through task analysis of several occupational clusters. The development of a sequential content structure was also based on these mathematics competencies. After completion of this program the student should be able to: (1) know that "sum" indicates the operation of addition, (2) add two or three numeric fractions of the form a/b where 0 is less than a/b and when a/b is less than 100, (3) add two or three fractions of the form k/y, where 0 is less than k when k is less than 100 and y is the same literal denominator for all fractions, (4) add two or three literal fractions with the same denominators, and (5) add mixed fractions of the form Xa/b, where 0 is less than (X,a, and b) and these are less than 100. The material is to be used by individual students under teacher supervision. Twenty-six other programed texts and an introductory volume are available as VT 006 882-VT 006 909, and VT 006 975. (EM)