Solving Complex Story Problems

[Dragon photo above by monkeywingand treasure chest by Tom Praison via flickr.]

Solving-Complex-Story-Problems

Let’s play around with a middle-school/junior high word problem:

Cimorene spent an afternoon cleaning and organizing the dragon’s treasure. One fourth of the items she sorted was jewelry. 60% of the remainder were potions, and the rest were magic swords. If there were 48 magic swords, how many pieces of treasure did she sort in all?

[Problem set in the world of Patricia Wrede’s Enchanted Forest Chronicles. Modified from a story problem in Singapore Primary Math 6B. Think about how you would solve it before reading further.]

How can we teach our students to solve complex, multi-step story problems? Depending on how one counts, the above problem would take four or five steps to solve, and it is relatively easy for a Singapore math word problem. One might approach it with algebra, writing an equation like:

x - \left[\frac{1}{4}x + 0.6\left(\frac{3}{4} \right)x  \right]  = 48

…or something of that sort. But this problem is for students who have not learned algebra yet. Instead, Singapore math teaches students to draw pictures (called bar models or math models or bar diagrams) that make the solution appear almost like magic. It is a trick well worth learning, no matter what math program you use.

Continue reading Solving Complex Story Problems

How Can We Teach Problem Solving?

We continue to plan our co-op courses for next fall. Some of the classes I had hoped for will not happen, and my children are going to have to make some tough choices between the remaining topics. Unfortunately, they have not yet mastered the ability to be in two classrooms at once.

I have three math courses to plan, and I think I will focus as much as I can on teaching math through problems, even at the elementary level. These are once-a-week enrichment classes for homeschooled students, so I assume they have a “normal” math program at home. I want to introduce a few topics they might not otherwise see, to deepen their understanding of the topics they have studied, and to give them a taste of that “Aha!” feeling that comes from conquering a challenging problem. Has anybody done something like this, and can you recommend some good resources?

Continue reading How Can We Teach Problem Solving?

Answers and Other Tidbits: The Pharaoh’s Treasure

[Read the story of the pharaoh’s treasure here: Part 1, Part 2, and Part 3.]

I confess: I lied — or rather, I helped to propagate a legend. Scholars tell us that the Egyptian rope stretchers did not use a 3-4-5 triangle for right-angled corners. They say it is a myth, like the corny old story of George Washington and the cherry tree, which bounces from one storyteller to the next — as I got it from a book I bought as a library discard.

None of the Egyptian papyri that have been found show any indication that the Egyptians knew of the Pythagorean Theorem, one of the great theorems of mathematics, which is the basis for the 3-4-5 triangle. Unless a real archaeologist finds a rope like Alexandria Jones discovered in my story, or a papyrus describing how to use one, we must assume the 3-4-5 rope triangle is an unfounded rumor.

Continue reading Answers and Other Tidbits: The Pharaoh’s Treasure

Carnival, Carnival, Carnival

The 120th Carnival of Education is now up and running at I Thought a Think. As always, a wide variety of interesting articles to browse. Enjoy!

Carnival of MathematicsEdited to add: Oops! I missed the 8th Carnival of Mathematics last week.
My favorite posts mostly came in pairs.

Two puzzles from MathNotations:
When Curves Collide
Going off on Tangents

Two brainteasers from SharpBrains:
The Unkindest Cut of All
The Really, Really, Really Big Number

Two mind-blowing infinity puzzles that were fun to read, even though I didn’t really understand the answers:
Cats in a Tree
Dogs in a Mineshaft

And the odd-one-out is a history post:
Calculators: Past, Present and Future

The Secret of the Pharaoh’s Treasure, Part 3

[In the last episode, Alexandria Jones discovered a mysterious treasure: three wooden sticks, like tent pegs, and a long loop of rope with 12 evenly spaced knots. Her father explained that it was an ancient Egyptian surveyor’s tool, used to mark right angles.]

Back at the camp, Fibonacci Jones stacked multi-layer sandwiches while Alexandria poured milk and set the table for supper.

“Geometry,” Fibonacci said.

“What?”

Geo means earth, and metry means to measure. So geometry means to measure the earth. That is what the Egyptian rope stretches did.”

Alex thought for a moment. “So in the beginning, math was just surveying?”

“And taxes…”

Continue reading The Secret of the Pharaoh’s Treasure, Part 3

Quotations IX: A Good Student Is…

Aaaargh! My Internet service is on the brink again. But since I had to run into my husband’s office to check email, I’ll take a few minutes to post a quick note. Here are a couple of quotes especially for teachers:

The only teaching that a professor can give, in my opinion, is that of thinking in front of his students.

Henri Léon Lebesgue

A good student is one who will teach you something.

Irving Kaplansky

Geometry: Can You Find the Center of a Circle?

Is it possible that AB is a chord but NOT a diameter? That is, could circle ABC have a center that is NOT point O?

For the last couple of days, I have been playing around with this geometry puzzle. If you have a student in geometry or higher math, I recommend you print out the original post (but not the comments — it’s no fun when someone gives you the answer!) and see what he or she can do with it.

[MathNotations offers many other puzzles for 7-12th grade math students. While you are at his blog, take some time to browse past articles.]

The Secret of the Pharaoh’s Treasure, Part 2

[In the last episode, Alexandria Jones, daughter of the world-famous archaeologist, caught her father’s arch-enemy trying to uncover the Pharaoh’s Treasure.]

…”I can’t believe it!” Simon Skulk threw down the last stone in disgust and walked away. At the mouth of the cave, he turned back and shook his fist. “You haven’t seen the last of me, Alexandria Jones.”

Her muscles aching, Alex sank to the ground and hugged her dog. The she gave him a little push toward the front of the cave. “Rammy, go get Dad.”

Ramus barked once and took off running.

Alex turned back to look at the Pharaoh’s Treasure. Where the last stone had stood was a hole. In the hole lay three wooden sticks, like tent pegs, and a long loop of rope with 12 evenly-spaced knots.

What could it be?

Continue reading The Secret of the Pharaoh’s Treasure, Part 2

The Secret of the Pharaoh’s Treasure, Part 1

Alexandria Jones stood outside her father’s tent. The glare of the sun on the rocky desert hurt her eyes. Holding up a hand to shield her gaze, she spotted her dad (the world-famous archaeologist) arguing with the foreman.

Poor Dad, she thought. He was sure this was the right site, but so far he’s found nothing.

She looked down at her feet, where her faithful dog Ramus waited, panting. “Well, Rammy, it looks like Dad will be busy for while. What do you say? Shall we go exploring?”

Alexandria ducked into the tent for her backpack and canteen.

Thump! Something bounced against the side of the tent. Ramus barked.

Alex stepped outside and looked quickly around. No one was in sight. She saw a fist-sized rock beside the tent, with a note tied to it. She picked it up and read:

Ha! The real Pharaoh’s Treasure lies under a pyramid of stones, and it’s mine. You can’t stop me this time! —Simon Skulk

Continue reading The Secret of the Pharaoh’s Treasure, Part 1

Spring Cleaning My Blog Links

Our whole family is coming down with something again. What a nuisance!

Since I don’t feel up to real cleaning, I guess it’s time to spruce up my sidebar. If you haven’t posted since November or December of last year, you’re outta there. And for those of you who use Blogger — well, I’m sorry, but if I get a persistent “Blogger: 404 – Page Not Found” then you’re gone, too. If you are still actively blogging, please send me an email.

Continue reading Spring Cleaning My Blog Links