Calculation is an essential aspect of chess, as it allows players to evaluate the potential outcomes of different moves and choose the best course of action. The process of calculation involves considering all possible moves and responses, and predicting the consequences of each move. However, calculation can also be a challenging process, and players often make common mistakes while calculating. These mistakes include failing to consider all relevant factors, such as the position of the opponent's pieces and the pawn structure, and underestimating the opponent's potential responses. Additionally, players may also overlook key tactical opportunities, such as a potential discovered attack, and make imprecise evaluations of the position. In this interaction with WGM Divya Deshmukh, GM R B Ramesh discusses and shares his learnings on many of these key issues through some illustrative examples.