Is 2023 a special number?
1998 was a Harshad year.
What do you notice about the number 2023?
What is a Harshad number?
Does 2023 meet the criteria?
Big deal? Rare? Often?
Number Sense
Genres
Grade
How many feet of lights should I buy for my tree?
Check out our Christmas Tree! We need to buy lights for the tree. Without calculating, guess how many feet of lights we will need. What information would help you t...
Winter Solstice 2023
It is really dark out now. Why is that?
Students appreciate how their latitude effects the darkness of their late afternoon location as they study the earth's tilt and the logic of da...
Do I have enough wrapping paper?
In this problem based activity students first guess and then try to calculate whether they will have enough paper to wrap this present without taping pieces of wrapping paper together.
Con...
Wind chill
The weather forecasters tell us what the wind chill temperature will feel like. How do they figure out that number? In this activity students use the National Weather System chart ...
The Algebra of Magic Squares
Have you seen magic squares before?
How could a teacher use these puzzles to help students with different number skills?
How few blank cells could you leave?
Are there any special cel...
How big could this mid-term election be?
Will the November 8th 2022 election bring record number of voters to the polls? Students get a chance to understand what the usual percentage of voters is, look for trends and central tende...
I need help raking my leaves
Brian has spent too much time thinking about his leaves. He's worried about raking them alone and thinking about how long the job would take if people helped.
In this activity students see the inve...
The size of chocolates
In this activity students assume that all of our pieces of chocolate are about the same thickness and proceed to approximate their volumes by comparing only their surface areas.
Consider sh...
Inflation and the cost of gasoline
In 1980, one gallon of gasoline costs $1.22. Today's prices are a lot higher. Is that because the price has gone up or because in 1980 you could buy a lot more than you can buy today for...