“…The second-order backward difference approximation for the second derivative has first-order accuracy The fractional relaxation and subdiffusion equations are important fractional differential equations. Their analytical and numerical solutions have been studied extensively [3,9,12,13,14,17,20,31,38,42,44,54]. In this section we determine the numerical solutions of the fractional relaxation and subdiffusion equations which use the compact modified L1 approximation for the Caputo derivative…”