Showing your kids how to work with currency is probably the most straightforward way to demonstrate to them how math figures into our daily lives. Money is also the best model of our base-10 (decimal) number system. While children will likely encounter lessons about money in the classroom in first or second grades, it is also appropriate for parents to introduce these concepts at home as early as preschool and kindergarten. Here is a brief outline to guide you as you teach your child how to use money:
By the end of second grade, children should know the names and values of coins:
a penny = 1 cent a quarter = 25 cents a nickel = 5 cents
a half dollar = 50 cents a dime = 10 cents a dollar = 100 cents
By the end of third grade, children should be familiar with the basic equivalents:
20 nickels = 10 dimes = 4 quarters = 2 half dollars = 1 dollar
1 dime = 2 nickels
1 quarter = 5 nickels
1 half dollar = 5 dimes = 10 nickels
Exploring other coin combinations (such as 3 quarters = 15 nickels and 15 dimes = 6 quarters) will help your child develop fluency in working with currency in different denominations.
At this age, you can also build on other skills they’ve learned in math class by introducing basic word problems involving money:
How many dimes have the same value as 6 quarters? ...40 quarters?
An old fashioned name for a quarter is ‘2 bits’. How much is 8 bits? 1 bit?
Counting piggy banks full of coins is an excellent way to get children accustomed to using money. (It’s also a great way to teach kids the benefits of saving money!)
Making change is another useful skill that can be introduced in late first grade/early second grade, and ideally, should be mastered by fourth grade. Kids should learn how to make change from:
a half dollar
two/five/ten/twenty/one hundred dollars
Here are some sample questions:
You have a dime. If you spend 6 cents, how much will you have left?
If you want to buy something that costs 50 cents, and all you have is 47 cents, how much more do you need?
If you want to buy something that costs a dollar, and all you have is 78 cents, how much more do you need?
If you buy something that costs 18 cents, how much change will you get from $2.00?
If you buy something that costs $1.46, how much change will you get from $2.00?
If you buy something that costs $12.89, how much change will you get from a 20-dollar bill?
Dan Gehlbach is the owner and center director of Mathnasium – The Math Learning Center, located in West Des Moines and within the Waukee School District. Dan lives with his wife and 2 daughters in Urbandale. Year round, the center helps kids get caught up, keep up and get ahead while they develop confidence and a love for math. For more information call 440-MATH or consult the web site at www.mathnasium.com/westdesmoines.