Quickly finding the quintuple of 21

To quickly find the quintuple of 21, you multiply 21 by 5. This operation means you are taking the original number 21 and increasing it fivefold. Multiplying by 5 is the same as adding 21 to itself five times, which simplifies the calculation and gives the total amount in just one step. When you calculate 105 by multiplying 21 by 5, you receive the quintuple of 21. This approach is efficient and applies to any number you choose for 21. For example, if 21 were 7, then 7 multiplied by 5 would give 105 as 35. This method allows you to quickly find five times any number using simple multiplication.