Now, let's review using coins to make up multiplication and division number families. Remember how coin problems with nickels and dimes work? Let's practice a coin problem with nickels.
First, we'll work with a problem that tells how many coins you have.
How do you know that 5 is the first lesser (smaller) number for this family? It is because we know that each nickel is worth 5 cents. Now figure out what number to use for N with the number of nickels. There are 7 nickels. So you work the multiplication problem 5 × 7 to figure out the greatest (larger) number. The product, or answer, equals 35 cents! Multiplying 5 times 7 equals 35 (5 × 7 = 35).
Now how about a coin problem that tells how many cents you have?
You write 5 for the first lesser number. The problem shows the total number of cents. This is your greatest number. So you write 35. To figure out the number of nickels, you divide 35 by 5 and you have 7 nickels! Dividing 35 by 5 equals 7 (35 ÷ 5 = 7).
