Teaching Math Application: A Lesson in Sales Tax

“Mom, can we buy this?  Can I have that?  Everyone else has one, why can’t I?”

So…this is a little different for me, but it goes along with having some experience with homeschooling, raising boys and using real life to teach practical lessons.  So, here we go:

You know the scenario.  You go into a store with your child and you pass by the toy section….or the book section, as would be the case with my boys.  They see something they want to purchase and the hounding begins (see above).  Actually, it doesn’t last long in our family because the boys have been programmed to “cease and desist” early enough before consequences ensue (it took years, my friends…years).  Of course, as the boys are growing up, they are beginning to have access to their own funds and it has provided quite an opportunity over time to teach them how to spend, how to save…and what a price tag REALLY means.

When young, they see numbers and think that the cost of the item is just that – $24.99, $8.99, etc.  They take things at face value and are not privy to the knowledge that, “Oh, no, my son…that doesn’t mean that you think it means.”  Since my boys LOVE math…and I mean LOVE math like it was candy…this has given my husband and me tremendous opportunities to teach our three nuggets about sales tax and how to calculate it.  Throw in some decimal work and multiplication…and we have a life lesson taught using numbers!

As a former homeschooling parent (and one who is seriously considering it again for the youngest), I have searched high and low for tremendous resources to use in supplementing whatever curriculum I have selected for the boys.  Early on in our homeschooling adventures, I had several of my friends direct me to the site education.com.  Interestingly enough, I was recently contacted by someone working with education.com and asked if I would be interested in sharing a project from the site on my own blog.  The request brought me back to the site to see all they offer and I was still impressed.  From free material to membership opportunities for teachers (both parents at home and teachers in the brick and mortar classroom), I liked seeing what I saw and the opportunity sounded exciting, so I agreed to share and she sent me a lesson to post.

Get this – the lesson sent to me was a MATH lesson – it felt like she knew me!  I told you above…my boys love math!!!  I mean LOVE math!!  My 11 year old is already trying to figure out how to ensure he will be able to take on multivariable calculus by his senior year (if not earlier!!).  All three boys are focused on becoming engineers in some way, shape, form or fashion, so math is a big deal for our family. This was a good fit for us.

Below is the lesson that was sent and my youngest took on the task of working various applications with it.  As noted above, numbers are like candy for him.  This was a great way, all laid out, to talk about multiplication, decimals, money and sales tax and I, myself, found the application of the lesson very useful.  To find it on the site, among other lessons in multiplications, simply click on the following link:


Get Sales Tax Savvy

By late elementary school, students are expected to perform basic multiplication problems involving decimals. For a fun activity that takes the dull out of decimals, show your child how to gain a better understanding of decimals – as dollar amounts! Throw in a practical lesson in money management, and you’ve got an activity that will give your child math practice, as well as real-world savings savvy.

Maybe your child really wants to purchase a new bike for the summer, or another special item. Like many kids, he’s probably unaware that the bike will cost more than what is stated in the catalog because sales tax is added. However, it’s possible to save money on the bike by “shopping around” for the city with the lowest sales tax and buying it there.

What You Need:

  • Sales tax chart for your local area
  • Calculator
  • Paper
  • Pencil

What You Do:

get-sales-tax-savvy-chart (3)

For example:

  • 7.5% = .075
  • 10% = .100
  • 6.5% = .065
  • 5% = .050
  1. Begin by asking your child to find a bike, or other desirable item, in a local store catalog. He should write down the listed price of the bike and shop around for similar bikes at a lower price.
  2. Once he has chosen the bike he wants to buy, have your child determine the best city in which to buy the bike. Explain to your child that local cities have different sales tax rates and buying the bike in the city with the lowest rate will save him money. Show him the list of local tax rates and help him make a chart like the one below.
  3. As you make the chart with your child, explain how percentages change to decimals by moving the decimal point two places to the left and adding a zero.
  4. Give your child a calculator to multiply the decimal by the cost of the bike to get the sales tax. Finally, for each city, add the sales tax to the cost to get a total.
  5. Discuss with your child the best place to make his bike purchase. With the money he saves on the bike, your child can start saving for his next big purchase!

Footprints Mom note: My high schoolers use calculators because of the higher math courses they take, but I usually encourage my youngest to use pen, paper and his own brain.  The calculator will help with a quick answer and it’s good to know how to use technology, but this would also be a fantastic way to incorporate brain power and sharpen the skills and memory gained by writing things out.  

Whether homeschooling or teaching in a brick-and-mortar school and just looking for fresh ideas, education.com is a good resource to keep in your tool box (or pencil box).   It’s a great place for parents and teachers to go when they are trying to find some creative ways to apply the lesson being taught.

I encourage you to check out the site ~ see if there are things on there that you may find useful.  They boast over 10 million parents and teachers using their award winning resources.  Should we choose to homeschool again, I can see myself visiting education.com often to supplement and provide various ways to apply the knowledge he is learning.

Disclaimer: As noted above, I was contacted by a consultant working with education.com and asked if I would be interested in posting one of their lesson plans to my site.  I gladly and freely agreed and was not in any way compensated for this post or my opinion.   All viewpoints are 100% my own. 
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