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: The Metric Worm vs. The Phantom Number

The Phantom Number lurks within any dreaded fraction just waiting for an opportunity to scare the bejeebers out of some unsuspecting kid learning how to change a fraction into a decimal. I ain't afraid of no ghost number, are you? Come on. With the Metric Worm in hand, we can do this together.

Uhh...you go first. I'm right behind you.

Whole numbersYou've got the supplies, right? Two index cards, tape, a Sharpie, a pencil, and some paper? To slay this creepy phantom let's tape the cards together and make long worm. We'll place the decimal at the center of the joined cards. The whole numbers go on the left, remember. We're going to stretch this brave wiggler all the way to the hundred-thousands place.

Going to the left away from the decimal we make a mark for the ones place, the tens place, the hundreds place, the thousands place, the ten- thousands place, and the hundred-thousands place. Hope this doesn't hurt the little fella.

Metric numbersNow the metric numeral places go on the right. We're doing to pull the little guy all the out to the hundred-thousandths place. This is the scary part. Hold my hand.

Make marks for the tenths place, the hundredths place, the thousandths place, the ten-thousandths place, and the hundred-thousandths place. Ouch!

Oh, my gosh! Will you look at the fraction? 579607 49/1000! I gives me chills to think where we'll place that ugly 49/1000 on the worm. Looks at those frightening zeros! Where will we put them?

We can do this. Breathe.

Lay the worm on the page. Remember the decimal separates the whole number from the fraction. Mark the decimal on the page. To the left of the decimal write out the long whole number by placing each numeral above the proper place value. 

The Phantom is trying to trick us here, but we won't fall for it. He is asking for 49 ten-thousandths. Let's give it to him. Put the nine over the ten-thousandths place. Put the 4 over the hundredths place.

Oh! Do you see him? The Phantom Number? There he is...howling above the tenths place.

Let's put an end to his haunting and write a zero above the tenths place.

There!

Take that Phantom!

BOO back at 'cha!

Simple Saturday Prep: The Metric Worm vs. The Phantom Number

(Cue  scary harpsicord music.) We are about to enter a realm few people have faced with confidence.

Just look at this poor fellow. See what converting fractions to decimals did to him? Too bad he didn't know about the Metric Worm. Tragic, isn't it?

For tomorrow's ghoulish pleasure you will need 2 index cards, a Sharpie, some tape, a pencil, and paper.

All for now. (Cue evil laughter.) Bwwaaa ha ha!

Simple Saturday: The Metric Worm

Here it is! The one, the only, the amazing Metric Worm!There are lots ways to use my versatile friend, the Metric Worm. This little buddy really helps to take the panic out of visualizing fraction/decimal equivalency. I've coached many a tearful student with this tool. Today I will demonstrate just one of the numerous ways to use the Metric Worm.

 Instead of high-tailing it to the teacher store and dropping close to $10.00 on the latest expensive educational gizmo, just get yourself a index card and a marker. I jazzed mine up with a picture. No need for that, however, as a bribe, I have been known to allow a student to jazz up their Metric Worms AFTER they have proven that they know how to use it! Alls fair in love and teaching.

Here's how it works.

Decide upon a very long number. I choose 92,743. Write it out.

Now, rewrite your number as a whole number and a fraction. I changed my number into 927 43/100. How in the world can we rewrite this number as a decimal?   

Let's look at the number. The whole number is 927, right? And the fraction is 34/100. 

Okay now, let's look at the worm. We know that a decimal separates a whole number from the fractional portion of the number, yes? So, we simply rewrite that big, scary fraction as a decimal by laying the worm on the paper and initially making the decision where the decimal should go. Then we write the whole number to the left of the fat decimal. I wrote my 9 about the hundreds place, the 2 above the tens place, and the 7 above the ones place. Now, the terrifying metric part. I simply put the 4 above the tenths place (decimeters) and the 3 above the hundredths place (centimeters). Easy.

Let's do it again. How about changing 92 743/1000 into a decimal? Here's where the tears begin to flow. Something about working with the 1000ths place always seems to unleash the waterworks. Take a breath. There are no worries with the worm, remember?

Just lay the worm on the paper. Where does the decimal go? Where does the whole number go? How about that nasty old metric number? Hey! Look at you! You've got it, smarty pants!

This Metric Worm illustrates whole numbers into the hundreds place and metrics into the thousandths place (millimeters). Once the kiddos understand this wee little worm why not branch out into the millions and millionths? The gazillions and gazillionths? Stretch that wiggler. This is the kind of mental-gymnastical thinking that creates enthusiam out of a concept that was once confusing. Kids love numbers. They really do. Once they understand, they love to think big or metric small. No limits! Have fun with this.

Give credit where credit where credit is due, right? I stole this idea from a good teacher my daughter Taylor once had. Though I cannot remember her name right now, her brilliance lives on.

Simple Saturday Prep: The Metric Worm

No, I didn't make up this stupid joke. I promise.Let's have some wiggly fun with decimal place value, shall we?

"What?" you ask. "How can working with metric place value be fun?"

When you know a cheater like the one I'm about to show you working with metrics can be a blast, especially when you're a geek like me.

Supplies needed are an index card, scissors, a Sharpie, and your brilliant self!