**I think the answer is C: Yes And No.**

**Scenario:**I'm on a shopping trip. I buy diapers, clothing, shoes, food, and I have a coupon for toilet paper. Oh, I have to buy a few things for my charity. I fill my cart and proceed to the checkout. An associate scans my purchases (the charity stuff first), bags everything and hands me the two receipts. Now, let's go back to the empty shopping cart. For simplicity sake, let's say I only have my two youngest with me. Did I use Common Core?

Well, when I looked at the diapers, I had to decide which brand, diaper size, and package size I was going to buy. Except, I already know from previous experience that certain brands are cheaper because they tend to leak more and there tends to be more defective diapers in the package. I also know that contrary to the pictures on box, certain brands will better fit my baby's body shape. And my baby is a smaller size in some brands than in others. In addition to my personal knowledge, I had seen ads to help me determine that "Lil' Movers" is comparable to "Cruisers" but that "Baby Dry" is a completely different type of diaper.

Armed with all this knowledge, I stand at the baby aisle and scan the prices. Even when I decide with brand and type of diaper I want, I still need to determine which size package will be less expensive. I have pulled out my calculator in the past to check my estimates, but I don't have my calculator with me today. So how do I decide which package to buy? Well, when I last calculated, 32 diapers costs $9.97, and diapers costs 96 $19.78, and 178 costs $39.95. So the middle package was the cheapest. But the big box is on sale today for $35.97. Now, I know that there was a difference of about 2 cents per diaper, so $4 (or rather $3.98) off the original price would make the box now slightly cheaper than the middle sized package. I know this because I rounded 178 to 180 and multiplied 100 by 2 (200), and 80 by 2 (160), then added them together (360). Then I added 54 (300+60+50+4). Now I have 414, which I convert into $4.14. But when I rounded up, I added two diapers, so if I take off the original price of those two diapers of about 40 cents (4.14 - .15 = 3.99, 3.99 rounds to 4.00 - .25 = 3.75, 3.75-1=3.74) then I know that discount of anything more than $3.74 is going to make that box cheaper. Oh, wait, how did I know that the diapers cost about 20 cents each? Well, I remember that, from the last time I calculated the price of this brand of diapers with a calculator (price/number of diapers), each diaper was about 20 cents give or take a cent.

**On paper, this problem looks really complicated, and I haven't even bought diapers yet - the first item on my list!**But I didn't stand in that baby aisle more than two minutes because I'd already accumulated all that knowledge before this point of my shopping trip and after a quick mental jumping jack session, I knew which package of my favorite brand of diapers to buy. Let's move on.

I need to buy a some shirts for myself. My self imposed shirt budget is $25 (plus tax). One shirt is on clearance for $12 and another is regularly $40 but is marked down 50%, and then another 25%. So do I have enough for both shirts? Well, 50% off plus 25% off is actually 62.5% off (25/2 = 12, 50+10+2.5=62.5). And that's not quite 2/3 of the price. 40 divided into thirds is 13 and 1/3 (30 divided into thirds is 10, and I know that 10 divided into thirds is 3 1/3, so added together make 13 1/3). Now, I know that it's going to be a little more than that, because 62.5% is less than 66 2/3% by about 4.16% (66-62=4, 0.66 -0.5=.16, 4+.16=4.16, and I'm making the executive decision to truncate, even though I know it would be 66 repeated infinitely). Now I know that 4% of $40 is $1.60 (40 time 4 equal 160, and move the decimal two places to the left) and .16% of $40 is 6.4 cents (4 times 16 is 64 and move the decimal four places to the left). So, add $1.664 to $13.333 and I will have the price of the item within a few pennies: $15.01 ($13 +$1= $14, 60 cents + 30 cents = 90 cents, 3 cents + 6 cents = 9 cents, and the partial will probably add another cent. Or two, depending on how the computer calculates.) Oh wait, how did I know to convert back and forth from fractions to decimals? Well, I remember that 1/2 =0.5, 1/3=0.33 repeated, and 2/3 =0.66 repeated. Yep, I just memorized it a long time ago.

So I don't have enough in my budget to buy both. Why did I need to find the exact price of second shirt anyway? I knew I'd be over budget almost from the start. But I really like this shirt. Do I like it $15 worth? How much will it bump me over? Well, $12 + $15 is $27 (10 +10 =20, 2+5 = 7). That's only $2 (7 - 5 = 2). Okay, I'll get both.

**I think I know why people hate common core.**I'm hating writing all this down. Even I didn't show

*all*my work in school. I keep thinking,

*Why can't I just do it in my head because in a normal setting I would anyway*. But I want you to see that we do use Common Core, or at least I do, so let's move on.

Next item: My son needs shoes. Again.

What I'm considering here is whether to buy the same shoes I bought last time he needed them, or look for a more quality pair that will last longer. First I need to figure out how long it's been. I remember buying them at the same time I bought a gift for my daughter's friend. The party was the first Saturday of last month, which matches the date of the first Saturday of THIS month (because February's and March's date usually fall on the same day of the week since it's not a leap year). So that's 28 days plus the 12 days after the first Saturday of March to get to today, or 40 days (20+10=30, 8+2=10, 30+10=40). I'm pretty sure I bought that present a few days before the party, so let's just say my son shoes have lasted 6 weeks (7 days in a week, 42= 6 times 7)

OK, I know from research that some shoes have more glue than others. Glue can last longer than stitched soles, but sometimes it doesn't. I have also observed that Character shoes are more cheaply made than non-character shoes of the same price. However, my son shoes are not wearing at the stitching or glue, but rather at the tread. In other words, his shoes aren't lasting long enough to come apart at the seams.

So I turn the shoes over and examine the tread. I want to find shoes with the thickest tread at the ball of the foot and the heel, because that's where my son's old shoes wear the most. The tread in the middle is unimportant. Finally, I find a shoe that I think will last longer, and I decide to try it even though it is $5 more than the old pair. If these shoes last just 2 weeks longer than the old ones, I know I will have saved money. How? Well, the old shoes cost $13 (well, $12.97), so they cost about $2.5 per week (13 divided by 6 = 2.5) and so a pair of shoes that costs $5 more would have to last 2 more weeks.

**Does your head hurt?**I give you permission to go to the end of this blog. I do have a point to all this. But I'm moving on to the next item on my list.

I walk down the canned food aisle. The math is easier here because the unit prices are generally printed next to the total price. However, I do have to estimate to make sure the prices make sense, because sometimes the unit price is not accurate.

I stop at the tomato sauce. I know from previous experience that early spring is a good time for canned tomato products. Maybe the prices go down to empty the shelves for the next crop. Maybe it's enough months out from the last crop and prices go down before the cans expire. Or maybe it's just meatloaf season. I don't know, and it doesn't matter why they go down, but just

*that*they go down.

As I suspected, the sauce is on sale. There are 8 oz cans, 15 oz cans, and 28 oz cans. Now, I know that a few ounces don't make much difference in my cooking, so I think of it this way: 1 big can = 2 medium cans = 4 small cans. I need one big can of sauce for each meal. I pick up the size that is the cheapest unit price. And see the rust on the lid. The can has not expired, but I know from research that it is not a good idea to buy a rusted can of tomato sauce. I decide on a different size can. A little more expensive, but rust free.

I buy other foods based on my meal plans, which are based on my family's tastes, my schedule, and the sales ads. Which I know from research, experience, observation, and communication. I won't site the sources here, but they come mostly from personal interviews and online research. I must tell you about the milk, though.

I buy 3 gallons of milk a week. You see, I did a calculation years ago and realized that as long as milk is less than $4 per gallon, it is cheaper than baby formula. I expected to adjust that for inflation, but the price of formula hasn't actually changed. So I buy formula for emergencies when they are infants, but once each of my children was old enough to handle milk (which is usually about the same time as they stop nursing) I stopped buying the formula altogether.

Now, the funny thing about milk is you never know which store is going have the lowest price on it. It looks like today it will be more expensive than that other store across town. So I have to determine if the savings is worth the extra trip. There's a lot to consider here. But first I have to know how much money I'm talking about.

Milk at that other store is $3.19 and it's $3.50 here, which is a difference of 31 cents (50 - 20=30, 30+1=31). Now, if gas costs $3.50 and my car gets 20 miles to the gallon, and the other store is 3 miles away, then it would cost about 50 cents in gas to get the milk (let's pretend that my car gets 21 miles to the gallon to make it easier, that means 3 miles takes 1/7 of a gallon, 350 /7 is 50 and move the decimal 2 places to the left).

**OK, CONFESSION:**I'm a Californian, so when I was estimating the difference between the two stores, I

*actually*thought, "Well, it takes me 10 minutes to get there, so that's about 5 miles." But then I remembered that the exits on the freeway only add up to 2 1/2 miles, and decided to put 3.

**Whew, glad to get that off my chest.**

So, 3 gallons would be a savings of 37 cents (3 times 30 = 90, 1 times 3 =3, 90+3=93, 90-50=40, 40-3=37). I'd use up that saving in time alone. Unless... I look at my list. If I need to go to the store for

*other*items, then it would be worth it to wait. I decide that I won't be going to the other store today, but I might later in the week, so I'll only get one gallon today. That means that I'll lose 31 cents now, but gain it back and then some because I'm not making a special trip for the milk later.

Now, last on my list is that toilet paper. I have a coupon for it. The interesting thing about coupons is how much you save depends on how the coupon is worded. The interesting thing about toilet paper is that you never quite know if you've actually saved any money.

The coupon I have is for $2 off. That makes it easy. I just look for the smallest package of toilet paper and I will get the most out of my coupon. BUT I have to check to make sure that the bigger packages of the same product aren't already cheaper without my coupon, in which case I would want to use my coupon on the bigger package.

I won't go over that math again because it looks a lot like the math I did in the baby aisle. Let's just say I've determined to buy the smaller package. I look at my coupon again grateful that it not a percentage coupon. Why?

Because if it was a 30% off coupon, I would have to figure out how much the big package is, and then the little package and finally compare the two. Percents take more steps to figure out in your head.

Now, I just grabbed the toilet paper and didn't bother trying to compare it with the other brands. Unlike most things, toilet paper is next to impossible to compare. There is 1-ply, 2-ply, and up. There's toilet paper that will soak your hand (ewww!) and toilet paper that feels like sandpaper (I'm not fond of sandpaper there). So I gave up figuring out the toilet paper pricing. I just found a few brands I trust, and discovered a few brands to avoid, and that's what I choose regardless of price.

Oh, my stuff for the charity! OK, I'll run and grab it. I need paper, markers, and glue. Nothing much to say here. Except I know from experience that certain marker brands work better and last longer.

I head over to the checkout. The stuff for the charity goes on the belt first. I'm paying cash for that and I need a separate receipt. I know from research that in some states I could get this purchase tax-exempt, but I also know that California works differently. So I mention that the purchase is for a charity.

The cashier scans the purchases and put them in a bag. She may not realize it, but she is estimating whether the paper markers and glue will all fit in one bag. They do.

The total comes to $17.34. I start to hand her a $20 bill, but the belt is still moving. Almost lazily, the cashier moves the clear plastic package so that the sensor no longer can see the laser on the belt. She may or may not be aware that she knows from experience (or research) that the belt stops moving when the laser light is blocked, but some packages allow the light to go through.

I hand the $20 and she counts back the change (4 + 1 = 5, 5 + 50 = 55, 30 +55 = 85, 85 + 5 = 90, 90+10=100, 100 = 1 dollar, 17 +1 = 18, 18 + 2 = 20). Except this is how she says it, "That's 18, and 20."

Now, the cashier scans my packages, while I silently decide which card to use. I know that there is plenty of room on one of them, but I like to use another one because I know from research that the rewards are better. However, I know that on the card I want to use, there was only $200 available and my husband has just made a payment today. I also know that it takes a full business day to clear, so I watch the subtotal on the register and estimate whether I will go over $200. Luckily the total is well under that amount, so I choose my preferred card.

OK, so I'm done with my shopping trip. And I haven't even mentioned how I spend most of the trip pushing my cart backwards because I know from experience and observation that my baby can wiggled out of the cart strap and turn around to go forward. But if I push the cart backwards, she stays in her seat.

Also, I haven't mentioned that keeping my other youngest happy and walking with me is well worth the extra cost of a RED container of chips, even though nobody else in the family likes that flavor.

Now, maybe you're thinking, "Not Me." Maybe you don't plan meals or impose clothing budgets or study shoe soles. Maybe you don't pay attention to whether the unit prices are accurate or care that sometimes the biggest box is not the best deal. Or Maybe you walk through store with a calculator and so you don't have to do any of it in your head.

**MY POINT IS:**People do use Common Core thinking in their everyday life. What they don't do is write down each thought process and how they arrived at each answer. They don't cite every source and always remember how they know facts. Some things people have just memorized. Some things people just know.

**THE OTHER SIDE OF THE COIN:**How can a teacher or a standardized test determine that students aren't just guessing? With 30 students in a classroom and several classes in each grade, there really is only one logical way: have them write it down. And that is how Common Core Standards are executed.

**ONE MORE THOUGHT:**A typical shopping trip takes 1 hour, this blog post took 5 times that.