Dividing with decimals is a challenging concept for students to grasp. Because they are not innate to student understanding, decimals must be grounded in concepts that are relateable to students. Money is both high interest and tangible, making it the ideal way to introduce decimal division.
What are decimals?
Decimals are fractions. They are parts of a WHOLE number. Within the U.S. money system, they are fractions of a dollar, or cents.
It takes 100 cents to make a dollar. For those of you that or in Great Britain, it also takes 100 pence to equal one pound. If you are in Mexico, 100 centavos is equal to one peso. For those of you elsewhere in the world, I would encourage you to look into your own money system and find ways to relate decimal learning to your students’ prior knowledge and experiences.
How can I use decimals to teach division?
Giving students a WHOLE dollar amount and asking them to share it equally among their small group is a great way to introduce or reinforce decimal division. I find it especially helpful to use hands on materials to make the tasks concrete for students. Play money is best, but I have also used base 10 blocks when I did not enough play money for students to use.
Try this!
1.) Give students a WHOLE dollar amount, I usually start with $5.
2) Students will work in small groups, no more than groups of 4, and will need to regroup amounts in order to split the money evenly. I tell students that the PLACE VALUE BANK only operates in values of ones, tenths, and hundredths so that it matches the number system. This means they will ONLY be able to regroup dollars into denominations of $1, $0.10 (dimes), and $0.01 (pennies).
3) Students may choose to regroup ALL at once, or as they go. Either situation works.
They will need to regroup the $5 into $1 values, giving each group member $1. For group members, this means that each member gets $1 and that there is $1 leftover.
The remaining dollar will then be divided into ten tenths, or ten dimes with each of the four members getting $0.2 of the final dollar.
The last two dimes are finally regrouped into 20 hundredths, or 20 pennies. When shared equally, each of the four group members would get 5 pennies.
The final amount for each group member is $1.25.
What do you think?
After several whole group situations, students can continue this practice using manipulatives and task cards. For a fresh take on task card practice in the classroom, be sure to check out the post below.
When building student knowledge of dividing with decimals, money offers students a relatable way to understand these concepts.
As you move forward with decimal division, transitioning from talking about dimes as tenths of a dollar and pennies as hundredths scaffolds student understanding.
Do you use money to introduce or teach decimal division? Share your thoughts in the comments below.
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