## Reducing Squares

Reducing Squares belongs to a category of puzzles called “matchstick puzzles” which were very popular in America during the last century. Most adults in those days carried small boxes of matches with them to light the many candles or lamps in their homes. Many of these same people had a favorite repertoire of matchstick puzzles… Continue Reading

## Making Word Problems More Engaging, Part Two

Dinnertime is a place stories are told at my house. One of my favorite storytellers is my husband Matt. When he tells a story, you feel like you are there. Stories are memorable, they can take us to another world, and for mathematics, stories bring context to the abstract. Our world is full of exciting… Continue Reading

## Shape Makers

Shape Makers is one of a large family of dissection puzzles which challenge students to assemble a series of smaller shapes to form larger ones. Tangrams, which gained popularity in the early 1900s, are perhaps the most common kind of dissection puzzle. In Shape Makers, four squares and eight triangles must be reassembled to create… Continue Reading

## Five Squares, One Square: Solution

In two previous blog posts I talked about a puzzle made up of five two by two squares, where each square was cut in two along a line from a vertex to the midpoint of a side. The challenge, which I gave in the first post, was to put the ten pieces together to form… Continue Reading

## Making Word Problems More Engaging, Part One

As I watched my daughter Bethany do her homework last night I had an Aha Moment. She complains almost every day that she has addition and subtraction homework. Apparently, she does not have her mother’s love of math. (I’m working on that.) Her paper had simple numeric addition and subtraction, and she decided that she… Continue Reading

## The Relative Riddle

This week’s Puzzle Corner is a classic riddle requiring reasoning to reconcile. (Please forgive the crude alliteration.) While many of you have encountered this riddle before and already know the answer, the riddle probably caused curious consternation (I beg your pardon once more) the first time you saw it. Riddles like the one presented here… Continue Reading

## Teaching Addition and Subtraction, Part Three

This blog post will be the final in a three-part series on teaching addition and subtraction. Part One talks about the Change Plus/Change Minus, and Part Two talks about Composing/Decomposing. Our last situation is Comparison. After reading Mathematics Learning in Early Childhood, I realized how foundational comparing relations (talking about two sets being more than,… Continue Reading

## How Many Squares?

In this week’s puzzle students are asked to find out how many squares are in the figure shown. This is not a difficult puzzle, but it does require some careful observation, organization, and counting. I encourage you to turn to the puzzle right now and give it a try before reading on. This will help… Continue Reading

## What Does Twice as Big Mean?

I’m often puzzled by the way we use phrases like twice as big. What does that mean? For example, I understand that if my debt 5 years ago was $10,000 and today it’s $20,000, then my debt is twice as big today as it was 5 years ago. I also understand that if one two-by-four… Continue Reading

## The Bridge Crossing Challenge

This week’s puzzle is a brief study of network theory whose roots began with a problem that was first approached in 1735 in Köningsberg, Prussia (now Kalinigrad, Russia), In this puzzle, students attempt to draw routes that cross every bridge in a bridge puzzle once and only once. Click here to download the directions for… Continue Reading