1. The problem asks to calculate \( cd \), which means multiplying the variables \( c \) and \( d \).\n\n2. To multiply two variables, you simply write them together: \( cd \).\n\n3. Without specific values for \( c \) and \( d \), the product remains \( cd \).\n\n4. If values for \( c \) and \( d \) are provided, substitute and multiply to get a numerical answer.