Journal of Approximation Theory
The Journal of Approximation Theory is devoted to advances in pure and applied approximation theory and related areas.
Editors-in-Chief: Paul Nevai and Amos Ron.
Here is the information page for the Journal of Approximation Theory at Elsevier which includes a list of the editorial board members and author instructions.
Journal of Number Theory
The Journal of Number Theory was founded at The Ohio State University in 1969 by Professors R.P. Bambah, P. Roquette, A. Ross, A. Woods, and H. Zassenhaus. It features selected research articles that represent the broad spectrum of interest in contemporary number theory and allied areas. A valuable resource for mathematicians, the journal provides an international forum for the publication of original research in this field.
Editor-in-Chief: Dorian Goldfeld.
Here is an information page for the Journal of Number Theory at Elsevier which includes a list of the editorial board members and author instructions.