Activity: Adding, Subtracting, Multiplying and Dividing with Decimals

If you were a fly on my classroom wall you would see my students working with grocery store flyers in order to practice working with decimals.

Materials:
* grocery store flyers (freeeeeeeee!)
* pencils, grid paper
* cookie recipes

Activities:

1. My Favourite Meal:
- Take a grocery store flyer to look through/explore/discuss/share.
- What are some of your favourite foods? (Take time to talk, discuss, share …)
- What foods would you choose to buy in order to make your favourite meal? (Note: You must choose a variety of foods from each of the food groups.)
- Record the foods and their prices in your notebooks.
- Now, pretend that you have purchased these foods and are heading to the check-out. How much would you need to spend in order to purchase everything? (Make sure the line the decimals up carefully!)
- Use your understanding of “percent” in order to calculate the tax.
- Let’s say you brought $100.00 with you to the store. What would your change be? (Make sure the line the decimals up carefully!)

2. A Birthday Dinner:
- Look through the flyer.
- What are some of your family’s favourite foods?
- What foods would you choose to buy in order to make your family’s favourite meal? (Note: You must choose a variety of foods from each of the food groups.)
- Record the foods and their prices in your notebooks.
- Now, pretend that you have purchased these foods and are heading to the check-out. How much would you need to spend in order to purchase everything? (Make sure the line the decimals up carefully!)
- Use your understanding of “percent” in order to calculate the tax.
- Let’s say you brought $250.00 with you to the store. What would your change be? (Make sure the line the decimals up carefully!)

3. _______’s Dangerously Disgusting Cookies
- Choose a cookie recipe.
- You must “keep” the main ingredients; ingredients that are common to most every cookie, such as flour, sugar and butter. You must replace everything else (e.g. salt, vanilla, chocolate chips, etc.) with something disgusting! Something that does NOT belong in a cookie recipe such as fish, mushrooms or steak.
- Pretend that you are going to the store to buy all of the items necessary to bake your “Dangerously Disgusting Cookies”
- Now, pretend that you have purchased these foods and are heading to the check-out. How much would you need to spend in order to purchase everything? (Make sure the line the decimals up carefully!)
- Use your understanding of “percent” in order to calculate the tax.
- Let’s say you brought $99.00 with you to the store. What would your change be? (Make sure the line the decimals up carefully!
Let’s say that you were the only one who liked the cookies and you only wanted to make half the recipe. How much money would you have to spend at the grocery store?
- Let’s say that everyone loves your cookies, (I know … weird, right?) and you need to triple the recipe. How much would you have to spend at the checkout?
(Note: My students love this activity … We share and draw pictures of our cookies too! Gross! ;-)

Hope you have fun!
Cheers,
Ally

P.S. I also often grab restaurant flyers & menus as well, and invite students to “order” meals for themselves, their friends and their family. We do a lot of adding, subtracting, multiply; & dividing. We even use “percentages” to calculate the tip as well.

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6 responses to “Activity: Adding, Subtracting, Multiplying and Dividing with Decimals

  1. I love the real application here! Students seem so disconnected from the process and cost of buying, preparing, and budgeting for meals. Kudos for making it applicable and engaging. I love those type of lessons. :)

  2. Pingback: This Week in Ontario Edublogs « doug – off the record

  3. I’m excited to try this after what we did with Feast Week last month in our fraction unit. So timely…I will be stealing. :)

  4. Love these real world ideas… so timely for our upcoming work with money. Thanks for sharing!

  5. Thank you so much for sharing such great decimal activities. I love how they’re so open-ended and so meaningful. I still need to teach decimals this year, and I really wanted to find some good application options. You have given me lots to think about. How do you introduce decimals to your students? Do you start with a problem, or do you start with a lesson? I always struggle with deciding on the best approach: to teach first, or to let students explore first, and teach second. I would love to know your thoughts on this!

    Aviva
    http://www.weinspirefutures.com

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