What mathematical topic is introduced when determining the total amount of money deposited by Joshua, who has collected 12,345 nickels?

To determine the total amount of money deposited by Joshua, who has 12,345 nickels, you start by recognizing that each nickel is worth $0.05 (or 5 cents). The calculation involves finding the total value of the collected nickels, which can be represented mathematically as a multiplication of the number of nickels by the value of one nickel.

When you multiply the quantity of nickels (12,345) by the value of a single nickel ($0.05), you are performing a multiplication operation involving decimals. This calculation is necessary to arrive at the total monetary amount deposited, which would yield a result in dollars. Therefore, this scenario introduces the topic of multiplying decimals, as it involves both whole numbers (the count of nickels) and decimal values (the value of each nickel).

The other options do not fit the context of this problem. Adding whole numbers would only be relevant if we were summing up quantities without a unit of value involved. Dividing fractions is not applicable in this case as we are not splitting any quantities or values. Rounding numbers could be introduced once a total is calculated, but it is not a part of the primary operation needed to determine the total amount based on the given information about