Leon’s Christmas Gift

Lo-shu turtle

Here is the simplest puzzle from the November/December 1998 issue of Alexandria Jones stories. The answer (and more puzzles) will follow.

Christmas gift for Leon (pdf, 68KB)

Edited to Add

More puzzles are now here:

Magic square puzzles

Answers are also posted:

Christmas puzzle answers

To Be Continued…

Read all the posts from the November/December 1998 issue of my Mathematical Adventures of Alexandria Jones newsletter.

The Golden Christmas Tree

Last time, Alexandria Jones and her family were on their way to Uncle William’s tree farm to find the perfect Christmas tree, and Dr. Jones taught us about the Golden Section:

The \; Golden \; Section \; ratio

|———————A———————|————B————|

A \; is \; to \; B \; as \; \left(A + B \right) \; is \; to \; A, \; or . . .

\frac{A}{B}   =  \frac{A + B}{A}  = \: ?

I gave you three algebra puzzles to solve. Did you try them?

  • What is the exact value of the Golden Section ratio?
  • If a 7-foot tree will fit in the Jones family’s living room, allowing for the tree stand and for a star on top, how wide will the tree be?
  • Approximately how much surface area will Alex and Leon have to fill with lights and ornaments?

Math Adventurer’s Rule: Figure It Out for yourself

Whenever I give a problem in an Alexandria Jones story, I will try to post the answer soon afterward. But don’t peek! If I tell you the answer, you miss out on the fun of solving the puzzle. So if you have not worked these problems yet, go back to the original post. Figure them out for yourself — and then check the answers just to prove that you got them right.

Continue reading The Golden Christmas Tree

A-Hunting They Will Go

Alexandria Jones and her family piled into the car for a drive in the country. This year, they were determined to find an absolutely perfect Christmas tree at Uncle William Jones’s tree farm.

“I want the tallest tree in Uncle Will’s field,” Alex said.

“Hold it,” said her mother. “I refuse to cut a hole in the roof.”

“But, Mom!” Leon whined. “The Peterkin Papers…”

“Too bad. Our ceiling will stay a comfortable 8 feet high.”

Continue reading A-Hunting They Will Go

The Christmas Present Quandary

Alexandria Jones hated using store-bought wrapping paper at Christmas. She tried to wrap each present as a hand-crafted work of art.

Last year, she did mini-scenes with plastic figures building cotton snowmen or skating on aluminum-foil ponds — and, for her brother Leonhard’s gift, her favorite creation: toy dinosaurs having a snowball fight. But those 3-D scenes got knocked about under the Christmas tree.

This year, she decided, she would wrap the packages flat. But then, how could she make them special?

Continue reading The Christmas Present Quandary

More Fun with Hexa-Trex

Hexa-trex turtle logo

My elementary Math Club students had fun practicing their math facts and “out of the box” thinking with Hexa-Trex puzzles. The object of Hexa-Trex is to find a path through all the number and operation tiles to make a true equation. The “Easy” puzzles are just the right level for my 4th-5th grade students, although they get stumped whenever the equations require Order of Operations. One girl enjoyed the puzzles enough to take our extra pages home for her dad.

Hexa-Trex puzzles were featured in the October issue of Games magazine, and now you can enjoy Hexa-Trex away from the computer with Bogusia Gierus‘s new book, The First Book of Hexa-Trex Puzzles. If you are thinking ahead to Christmas (can it be that time already?!), and if you have a puzzle lover in the family, this little book would make a fun stocking-stuffer.

Egyptian Math: The Answers

Remember the Math Adventurer’s Rule: Figure it out for yourself! Whenever I give a problem in an Alexandria Jones story, I will try to post the answer soon afterward. But don’t peek! If I tell you the answer, you miss out on the fun of solving the puzzle. So if you haven’t worked these problems yet, go back to the original posts. Figure them out for yourself—and then check the answers just to prove that you got them right.

Continue reading Egyptian Math: The Answers

Egyptian Geometry and Other Challenges

Rhind papyrus

Would you like to study “the knowledge of all existing things and all obscure secrets”? That is how Scribe Ahmose (also translated Ahmes) described his mathematical papyrus. Ahmose’s masterpiece is now called the Rhind Papyrus, after Alexander Henry Rhind, a Scotsman who was one of the first archaeologists to make meticulous records of his excavations (rather than simply hunting for treasures). Rhind purchased the papyrus from an antiquities dealer in Luxor, Egypt, in 1858.

Ahmose’s writing included a huge table of fractions as well as story problems, geometry, algebra, and accounting. Can you solve any of Scribe Ahmose’s problems?

Continue reading Egyptian Geometry and Other Challenges

Another Egyptian Math Puzzle

Pyramids clip artI have one last puzzle for those of you who are following my Alexandria Jones series on hieroglyphic math and the Egyptian scribe’s method of multiplication by doubling. Here is the “teaser” problem from the cover of the Sept./Oct.1998 issue of my newsletter:

One more Egyptian math puzzle (pdf, 53KB)

Continue reading Another Egyptian Math Puzzle

Egyptian Math Puzzles

What we know about ancient Egyptian mathematics comes primarily from two papyri, the first one written around 1850 BC. Moscow papyrus problem 14This is called the Moscow papyrus, because it now belongs to Moscow’s Pushkin Museum of Fine Arts. The scroll contains 25 problems, mostly practical examples of various calculations. Problem 14, which finds the volume of a frustrum (a pyramid with its top cut off), is often cited by mathematicians as the most impressive Egyptian pyramid of all.

Continue reading Egyptian Math Puzzles

Trouble with Percents

Can your students solve this problem?

There are 20% more girls than boys in the senior class.
What percent of the seniors are girls?

This is from a discussion of the semantics of percent problems and why students have trouble with them, going on over at MathNotations. (Follow-up post here.)

Our pre-algebra class just finished a chapter on percents, so I thought Chickenfoot might have a chance at this one. Nope! He leapt without thought to the conclusion that 60% of the class must be girls.

After I explained the significance of the word “than”, he solved the follow-up problem just fine.