Homeschooling Math Lessons at the Grocery Store

I recently went with a friend to a local dollar general store, and they had a huge going out of business sale. Everything in the store was marked off, and as we were walking through the store, my friend kept asking me the cost of items after the mark down. Being that it was a dollar general store everything there was $1, $2, $5, meaning there were no cents. At first I didn't even think of it, but when we got to the shoe aisle and a pair of shoes were 70% off of $10 and she asked how much they would be I thought, "Are you kidding me?"

We are both in our 20's and I started thinking, how could a person possibly not know what 70% off of $10 is. Then I realized that many people do not know and that even less teenagers coming out of high school know. This is one of the reasons that many of the parents I know are starting to homeschool their kids. So many kids are not learning the things they need to function in everyday life in our school system. Personally we are probably going to go with some unschooling, and some homeschooling, but based on the experience with my friend I thought what a great way to teach your children something they can use as grown ups.

Here is what I taught my friend, maybe is it not as easy as it sounds to me, but I have used it a few times, to show people how easy it is to get their mark down prices figured out. Say an item is $25, and it is 20% off. That would mean you have to pay 80% of the current price. What I do is multiply 25 * 8, and I get 200. Because you are using a percent in this (the 8 is equal to the 80%) you take off one 0, for the decimal that should be in front of the 8.

This is also a great idea for teaching rounding. Say you are in the middle of the store, and your child wants a box of cereal, and that brand is 15% off. That means you pay 85%, well the price of the box is $3.50 before the discount. Well in the middle of the store, I'm not going to know off the top of my head what 85 * 35 is, no way! So what I would do here is round, and because I am spending money and I don't want to over spend I round up, because if I over estimate I am less likely to make a mistake. I would also use subtraction here. I would say well 10% of $3.50 is $.35 + another 17 cents (to get 5%), so that would be 52 cents. And 52 cents off of $3.50 is $2.98, I round up and it is $3.

I hope you are with me so far. It really isn't too difficult. It is just training your brain to go around more difficult mathematics. That is what makes grocery shopping much easier. As for more rounding, you can simply point out prices as you go through the store and have your child round up or down, to different amounts of decimals if you wish, or just dollar points. Another grocery store lesson, is making change at the register, and once they have the percentages down, they can start to learn what the bags of cereal mean that say "Now 50% more than X brand". Just an idea to get your kids ready for shopping when they are old enough to run their own household.