Understanding methods to compute quadruple -21

To compute the quadruple of -21, we begin by understanding that -21 stands for any numeric value we choose. Quadrupling this value means taking -21 and multiplying it by 4. This operation increases the original number to four times its size, reflecting the concept of scaling a value by a fixed factor. The expression -84 = (-21 * 4) clearly shows how to perform this computation. By substituting -21 with an actual number, the multiplication process yields the quadruple. This step-by-step approach demonstrates that no matter the value of -21, multiplying it by 4 will always produce the correct quadruple, reinforcing the method's simplicity and reliability.