Ma. Lourdes P. Dela Cruz MATH IN A CHALLENGING WORLD / Ma. Lourdes P. Dela Cruz, Celedonia R. Hermano. - Marikina City : Instructional Coverage System Publishing, Inc., 2017. - 510 pages : Tables, Illustrations ; 28cm. English ISBN: 9717194905 Subjects--Topical Terms: Dewey Class. No.: 510 / D332m