Service
 Series Editor for ``Monographs in Number Theory'' published by World Scientific Publishing Company (20082012)
 Editor for ``The Ramanujan Journal'' published by Springer Verlag. (20022011)
 Editor for `` International Journal of Number Theory'' published by the World Scientific Publishing Company. (20052012)
 Reviewer for Zentralblatt Math published by Springer Verlag. (19992013)
 Reviewer for Mathematical Reviews published by American Math. Soc.. (19972012)

Referees for various journals beginning 1995. These journals include
 Acta Arithmetica
 Adv. in Math.
 Amer. Math. Monthly
 Bull. of Lond. Math. Soc.
 Canadian Math. Bull.
 Comptes Rendus Math
 Discrete Math
 Glasgow Math. J.
 International J. of Number Theory
 J. Comb. Theory (Ser. A)
 J. Lond. Math. Soc.
 J. Math. Analysis and Applications
 J. Number Theory
 Math. Zeitschritft,
 Monatshefte in Math.
 Proc. Lond. Math. Soc.
 The Ramanujan J
 Trans. Amer. Math. Soc.

Service at National University of Singapore:
 Academic advisor for Arts and Social Sciences Students majoring in mathematics (19972003)
 Strategic Planning Committee (member, 20002003)
 Curriculum Committee (member, 2001–2005) (member, 2007)
 Department Teaching Evaluation Committee (member, 2008).
 Academic advisors committee (member, in charge of second and third year modules) (2006–)
 Elected Member of Department Executive committee (AY 2008/2009)
 Member of the Discretionary Admission interview board (2003,2006,2010,2011)

Service (Ministry of Education)
 Judge for Singapore Science and Engineering Fair (2006, 2010, 2011, 2014)
 Supervisor for Science Research Programme (1997, 2003, 2005, 2007)
 Member of the Accreditation Committee for the NUS high school (Mathematics) (20062008).
 Member of Interview Board to select PRC scholars (2003, 2004, 2007, 2011).