Simple Saturday: The Magnetic Metric Worm - Converting Decimals to Percentages and Back Again

Got the goods? An index card, a Sharpie, pencil, paper, and something small that has magnetic appeal over you? Something that you just have to have. Something that you love! This messy girl pictured and I share the same lustful craving for something incredibly smooth, creamy, milky sweet and wonderful. Chocolate!!!!

Chocolate has a powerful magnetic pull on me. For a mouthful of that wonderful stuff I am willing to shift from place to place anytime. And, if you take it from me I will shrink back to where I began. Same goes for converting decimals to percentages using the Metric Worm. I'll show you what I mean.

This week's index card Metric Worm has only four place value marks on it; one for the ten's place, the one's place, the tenths place and the hundreths place. Note in the center of the worm there is a mark for the roving decimal. In addition, there are two opposing arrows, one pointing to the right toward a percentage sign and another toward the left toward a crossed-out percentage sign. Also note my magnet of choice...a Hershey's mini chocolate bar.

A slinky something to keep in mind: While we work with the percentage wiggler remember that, since there are only two zeros in the number 100, we're only going to be shifting two place value spaces.

Let's begin with changing a decimal to a percentage. Take, for instance, the number .25. How will the worm help us to change it to a percentage? Watch this.

Lay the worm on the paper. Rewrite .25 placing the decimal and the numerals in their proper places. Lay the percentage magnet to the right of the card (In my case, the piece of chocolate).  

Oooo! Oooo! I feel the magnetic pull one space to the right of the fat decimal. Notice that the decimal  has moved  between the number 2 and 5? To change the decimal into a percentage, AND to get my prize, let's move another space to the right. Remember the slinky something rule?

Ooooo. There's that pull again. Watch how we will move to right one more time. Think of the percentage sign as a magnet pulling the decimal toward it. All you need to do the change a decimal into a percentage is to move the decimal over two spaces to the right. That's all there is to it.

Yay! Not only have we changed .25 to 25%, the piece of chocolate is mine!

.25 = 25%

Easy, isn't it? Sweet, too.

All right, let's travel the other way. Let's change a percentage into a decimal. The same principles apply, only this time we will remove that magnetic pull of the chocolate percentage sign and will wiggle to the left through the two places.

How about let's transform 15% into a decimal. See how I have rewritten the numeral 15% using the Metric Worm as a guide? The number 5 is above the one's place and the number 1 is above the tens? Notice how my chocolate percentage magnet is holding things steady? Watch what happens when the percentage magnet is removed.

Without the percentage sign to hold it steady the wiggler begins to move to the left of the decimal. We're making a decimal out of a whole number, aren't we?

Here the decimal has moved between the number 1 and the number 5. How many spaces are we supposed move when working with percentages? Yeah! You're right! Two.

Here we go. Since we do not have that percentage magnet pulling on us any longer, the decimal is shrinking back one more space to the left.

Ta da! Look what we've done!!! Our number has now become .15!

So, without the magnetic pull of the percentage sign, or when we removed my chocolate magnet, the decimal shifted two place value spaces to the left changing 15% to .15. The marvelous Metric Worm does it again!!!! 

Enough of this decimal/percentage stuff. I can't stand it any longer.

Yum.

Yum. 

Simple Saturday Prep: The Magnetic Power of the Metric Worm

And...for my decimal transforming finale, I shall once again entertain you with yet another utterly amazing property of the marvelously mesmerizing magnetic power of our dear friend, the Metric Worm.

Ta Da!!!!!

Tomorrow I shall demonstrate the ease of converting decimals into percentages and back again, a fantastic feat you will not want to miss.

Supply list? An index card, a Sharpie, a pencil, and a tiny treasure of your choice. Something that you really like. Something you just have to have. Something that has magnetic power over you.

Intrigued? Good.

Simple Saturday: A Fraction War

Fractions can be deadly...well, tricky anyway. Just think about all of the wacky rules involved in computing with them entail. The larger the denominator the smaller fraction. Two fractions with completely different numerators and denominators can be equal. Now, how the heck can that be true? Don't even begin to talk about reciprocals or improper fractions. And then, on top of all of this, we have to reduce these babies? Fractions aren't playing fair, and that's all there is to it.

Years ago I worked at a school for at-risk high-schoolers, I loved that job. I clearly remember sitting beside with an ex-gang member with a tear-drop tatooed at the corner of his eye and the words 'love' and 'hate' tattooed on the flesh between his scarred knuckles and finger joints. As I presented the notion of reciprocal fractions, I noticed the hand clenching his pencil wasn't not the one with 'love' printed on it.

Gulp.

 After we spent a good bit time talking about the mental gymnastics behind working with fractions and playing my game, my decorated pal began to understand the illogical logic behind computing with fractions. The scowl behind the teardrop tatoo softened. "Is that all there is to it?" he asked. I answered, "Yep. That's it."

So, let's you and I play Fraction War.

First of all gather up some index cards and a marker.

Next, write a random sequence of fractions on the cards keeping in mind what your intent to comprehend might be with the game. Do you want to grasp the notion of the simple value of fractions? What is 1/2 as compared to 1/9 and so on? (Note: It may be helpful to have fraction manipulatives available to use when initially working with concepts such as these. There is no shame in your game if you need to concretely double check the abstract, illusive, and down-right-hard-wrap-your-head-around value of these wacked-out fractional representations. Say what? You're telling me that 1/12 is smaller that 1/5? How can that be? Five is smaller/less than/littler  than twelve that last time I checked. Well, check again. We're talking fractions, bro.)

So, after you've made a pack of cards....25 or more...you're ready to play. Decide with your partner whether you're going to play 'High' or 'Low', which mean that the larger fractions take the deck or the smallest ones cleans up. Just be sure that you agree about the rules of the game before you begin. (Believe me. This is the voice of experience talking here.)

Uh, oh! Like the regular game of War, you might hit a stale mate, that is when the players have pulled two cards of equal value, or 'equivalent fractions'. In the picture 4/8 is equivalent/equal to 1/2. If that happens (and it will, hence the name WAR!) the players should proceed to draw three extra cards from their stack on hand and place them face down from their stack.

And then flip the next card in their stack on top of the faced down group already on the playing table. In this case, if we had agreed to play 'High', the 1/8 would take that stack because 1/8 is bigger than 1/9.

The more cards you make, the longer the game takes. If you really want to challenge yourself, create an assortment of fraction cards with tenths, hundreths, and thousandths as denominators to be paired against decimal cards of equal value. It also great fun to play with improper and mixed fractions in the stack.

Yeah, I can be quite sadistic when it comes to fractions. I really like working with them. Blame it on Fraction War!