• Assistant Professor , From August 2014 to November 2022 , Ramjas College, University of Delhi
• Assistant Professor , From July 2011 to March 2014 , Shivaji College, University of Delhi
• Assistant Professor , From July 2010 to June 2011 , Miranda House, University of Delhi

1. Naokant Deo, Sandeep Kumar, Durrmeyer variant of apostol-genocchi-baskakov operators, "Quaestiones Mathematicae", Vol. 44:1,(2021), 1817--1834, DOI: 10.2989/16073606.2020.1834000, Publisher:  Taylor & Francis, SCIE.

2. Sandeep Kumar, Naokant Deo, Approximation of Generalized Paltanea and Heilmann-Type Operators, Matematicki Vesnik, Vol. 74:2 (2022), 101-109, Publisher: Drustvo matematicara Srbije, ESCI. texttt{http://www.vesnik.math.rs/vol/mv22203.pdf}.

3. Naokant Deo, Sandeep Kumar, Convergence analysis of semi exponential Post-Widder operators, accepted for publication in Miskolc Mathematical Notes, Publisher: Miskolc University Press, SCIE.

1. Presented a paper in an international conference on Evolution in Pure and Applied Mathematics, Akal University, Talwandi-Sabo, Punjab, India, Nov-16-22, 2022, with the title Rate of convergence of Durrmeyer variant of Apostol-Genochhi Baskakov operators.

2. Presented a paper in an international conference on Analysis and Its Applications (ICAA-23), Dept. of mathematics Shivaji College(DU), Feb-27-28, 2023, with the title Approximation of Difference Operators.