In this paper, we study the approximation on differences of two different positive linear operators (generalized Pǎltǎnea type operators and M. Heilmann type operators) with same basis functions. We estimates a quantitative difference of these operators in terms of modulus of continuity and Peetre's $K$-functional. We represent the rate of convergence, using modulus of continuity and Peetre's $K$-functional. Also, we represent Heilmann-type operators in terms of hypergeometric series.