Mathematics definitely has its place in a frugal lifestyle. Figuring out how much an item costs per ounce takes mathematics, as does adding up your expenditures and figuring out what percentage of your money is being spent in different categories.

However, there are some times where frugality has it's own set of mathematical rules, where doing the frugal thing means doing what may seem illogical to the mathematician. Yet it works.

The true frugalista will compare prices to figure out how to get the best buy for her money. However, the answer may not always be what it appears to be at first.

In this case, yes. Knowing myself, when faced with the choice of a few different treats, I can never decide and pick only one. I usually will buy two or three of those candy bars (or a huge order of sushi) and then regret it afterward because I have a stomach ache. I just have a craving for different delicious tastes in my mouth, so I have a hard time not getting one of each when I've decided to treat myself.

When I go to the store where they sell the chocolates by weight, I am able to get a variety of those treats, satiate my craving for a few different flavors, and still come out having spent less money than if I bought a few 75 cent candy bars.

Illogical math example number 1.

Chocolate chips are really expensive where I live, so I rarely ever buy them. When I was purchasing some foods in bulk, I learned that I could buy chocolate chips at less than half the price that I typically pay for them.

I bought 10 pounds of chocolate chips at this terrific price... and ended up eating them so much more frequently than I usually would, and ended up finishing up that huge stock in the same length of time that it usually took us to finish but one pound. Even though the chocolate chips were cheaper than usual, we ended up spending 5 times more on chocolate chips for that time period than we would have if we had bought just one regularly priced 1 pound bag of chocolate chips.

Sale prices don't save you money if you end up consuming more of an expensive product.

We don't usually consume store bought condiments or nuts or dried fruit, unless a specific recipe calls for them. Usually the recipe only calls for a small amount of each of these foods.

When purchasing things that you don't use on a regular basis, it doesn't matter how much you're spending per unit. You just want the cheapest container possible. It doesn't pay to get the cheapest container of mustard per pound if you won't use 25 pounds of the cheap stuff, and you could get a one pound container for twice as much money per ounce, but 1/10th the price of the container.

Ahh, you think grocery trips make logical mathematical sense?

You typically spend Y on groceries every 2 week period. You can either go to the store 1 time and spend Y on groceries, or spend A one trip, B the next, C the next, D the next, all within that 2 week shopping period, and assume that A plus B plus C plus D equals Y, because that's what makes logical mathematical sense...

But when grocery shopping, you need to consider the X factor.

That A that you spent that first shopping trip was not Y/4. No, A is equal to Y/4 + X. B, similarly, is Y/4 + X.

What is this X amount? This X is all that extra money spent each shopping trip because of the psychological tricks employed at grocery stores to get you to spend more money. You think that by dividing your shopping trips into smaller trips, you're just spreading out the time in which you spend the same money, but the X factor makes you end up paying 4X extra by employing such a shopping method.

Keep in mind that you need to be flexible when it comes to frugality. Use your brain, not just your calculator. Try to understand if what you're doing truly makes financial sense and saves you money; don't just take your calculator's word for it!

However, there are some times where frugality has it's own set of mathematical rules, where doing the frugal thing means doing what may seem illogical to the mathematician. Yet it works.

### Illogical Frugality Mathematical Rules

__What's really cheaper?__The true frugalista will compare prices to figure out how to get the best buy for her money. However, the answer may not always be what it appears to be at first.

**Those chocolates**. Today I bought myself and my son some chocolate to eat as a treat. We were in the grocery store and he saw the displays of candy bars near the check out counter, and of course he wanted one. I opted, instead, to walk with him to the store nearby where they sold things by weight. We picked out a few rum balls, peppermint patties, chocolate covered orange rind, chocolate covered nuts, etc. For that little bit, we paid $1.25. If I would have bought the cheapest chocolate bar at the grocery store, I would have paid 75 cents. Did I make the frugal decision?In this case, yes. Knowing myself, when faced with the choice of a few different treats, I can never decide and pick only one. I usually will buy two or three of those candy bars (or a huge order of sushi) and then regret it afterward because I have a stomach ache. I just have a craving for different delicious tastes in my mouth, so I have a hard time not getting one of each when I've decided to treat myself.

When I go to the store where they sell the chocolates by weight, I am able to get a variety of those treats, satiate my craving for a few different flavors, and still come out having spent less money than if I bought a few 75 cent candy bars.

Illogical math example number 1.

**Those chocolates**. No, this is not a typo. I guess I just have this thing with chocolates.Chocolate chips are really expensive where I live, so I rarely ever buy them. When I was purchasing some foods in bulk, I learned that I could buy chocolate chips at less than half the price that I typically pay for them.

I bought 10 pounds of chocolate chips at this terrific price... and ended up eating them so much more frequently than I usually would, and ended up finishing up that huge stock in the same length of time that it usually took us to finish but one pound. Even though the chocolate chips were cheaper than usual, we ended up spending 5 times more on chocolate chips for that time period than we would have if we had bought just one regularly priced 1 pound bag of chocolate chips.

Sale prices don't save you money if you end up consuming more of an expensive product.

**Condiments, nuts, and raisins.**We don't usually consume store bought condiments or nuts or dried fruit, unless a specific recipe calls for them. Usually the recipe only calls for a small amount of each of these foods.

When purchasing things that you don't use on a regular basis, it doesn't matter how much you're spending per unit. You just want the cheapest container possible. It doesn't pay to get the cheapest container of mustard per pound if you won't use 25 pounds of the cheap stuff, and you could get a one pound container for twice as much money per ounce, but 1/10th the price of the container.

__Grocery Trips__Ahh, you think grocery trips make logical mathematical sense?

**The X Factor**You typically spend Y on groceries every 2 week period. You can either go to the store 1 time and spend Y on groceries, or spend A one trip, B the next, C the next, D the next, all within that 2 week shopping period, and assume that A plus B plus C plus D equals Y, because that's what makes logical mathematical sense...

But when grocery shopping, you need to consider the X factor.

That A that you spent that first shopping trip was not Y/4. No, A is equal to Y/4 + X. B, similarly, is Y/4 + X.

What is this X amount? This X is all that extra money spent each shopping trip because of the psychological tricks employed at grocery stores to get you to spend more money. You think that by dividing your shopping trips into smaller trips, you're just spreading out the time in which you spend the same money, but the X factor makes you end up paying 4X extra by employing such a shopping method.

Keep in mind that you need to be flexible when it comes to frugality. Use your brain, not just your calculator. Try to understand if what you're doing truly makes financial sense and saves you money; don't just take your calculator's word for it!

**Do you have any other examples of things that seem mathematically the frugal alternative, but end up costing you more money?****Do you identify with any of what I wrote above?**