## Five Squares, One Square: Some Hints and an Extension

In an earlier blog post I proposed a puzzle made of five 2 by 2 squares, each of which had been cut along a line from a corner to the midpoint of an opposite side so as to form a right triangle and a trapezoid with two right angles. The challenge of the puzzle was… Continue Reading

## Alphabetical Puzzlers

This week’s Puzzle Corner is a collection of puzzles dealing with letters of the alphabet. While they are not necessarily mathematical in nature (although one could argue this point), these puzzles have a place in a well-rounded mathematics curriculum. Alphabetical Puzzlers is a collection of four puzzles that use letters of the alphabet in a… Continue Reading

## A-Point-ing Pennies

This week’s Puzzle Corner activity is a one-person game with a fascinating history that goes back thousands of years and spans three continents. Dominic Olivastro, in the book Ancient Puzzles, notes that archeologists found three curious etchings on the roof slabs of the ancient Egyptian temple at Kurna which date back to around 1400 BCE.… Continue Reading

## One Object Three Shapes: The Solution

In an earlier post, One Object Three Shapes, we posed the problem of finding an object that would appear to be a triangle when viewed in one way, a square when viewed in another way, and a circle when viewed in yet a third way. The challenge was to create an object that would fit… Continue Reading

## What’s the Difference?

I was helping my daughter, who is in kindergarten, with her homework. She claimed the homework was too hard. She was working on subtraction in her class and the instructions for her homework were: FIND THE DIFFERENCE. I thought to myself, does she even understand subtraction as a comparison situation? Was that the thinking her… Continue Reading

## The Eight-Digit Puzzle

Using a piece of scratch paper, cut eight rectangular cards that will fit in the boxes below. Write a 1 on the first card, a 2 on the second card, and so on, until you have the cards numbered from 1 to 8. The challenge in this puzzle is to place the number cards in… Continue Reading

## Time Marches On

This week’s Puzzle Corner activity is a simple problem with surprising results. The question posed in the puzzle is: “How many times during a day (24 hours) do the hour and minute hands of a clock point in the same direction?” The obvious answer seems to be 24, yet this is not correct. Students are… Continue Reading

## Five Squares, One Square

A while back I posted a five triangle puzzle that involved putting together five 30-60-90 triangles to form a single triangle. Of all of the dozens of puzzles that I own and have made over the years, that is one of my favorites because of the opportunities it provides for students to think about important… Continue Reading

## April Riddles

This week’s Puzzle Corner activity is a collection of riddles that are appropriate for the week that begins with April Fool’s Day. These riddles are the types of brainteasers loved by mathematicians and other people who enjoy mental challenges. Solving them will take logical reasoning, thinking outside the box, and persistence. These problem-solving skills are… Continue Reading

## Decomposing Numbers with Kindergarteners Part Two

In my last post, I talked about the connection between decomposing numbers and place value. Understanding how numbers can be decomposed into parts lays the foundation for breaking apart numbers into specific groups. These specific groups could be anything, but for our numeration system they will be ten. You may want to check out the… Continue Reading