This chart recently came out from the American Lung Association about air pollution in the United States. How would you present this data to Congress… Continue

In a class of 23 students, the chances are fifty-fifty that two of them will have the same birthday. Now that may sound impossible since… Continue

Spreadsheets offer us a nearly unlimited ability to develop and learn from case studies using real world data. We will focus mainly on climate change… Continue

Decimal Division is one of a series of Labs to help you understand and learn to use decimals. I think you will find it fun… Continue

Decimal subtraction is one of a series of Labs to help you understand and learn to use decimals. I think you will find it fun… Continue

Ratios can be written in a wide variety of different way: as fractions, as decimals, and as percents.,with a colon, with a slash, as a… Continue

Fractions are ratios that’s why we call them rational numbers (ratio numbers). If you think about fractions as ratios, how does this help you to… Continue

Create, manipulate, and explore triangles in this live interactive spreadsheet. On the surface, a triangle is being drawn on a graph, but the real magic… Continue

Fibonacci, the nickname given the great medieval mathematician Leonardo of Pisa, is connected in most of our minds with the Fibonacci sequence. Spreadsheets make wonderful… Continue

This is one of those math puzzles that come up in contests but which turn out to be quite interesting mathematically. Imagine a long hallway… Continue

What if you made a series of unit fractions with the odd numbers as their denominator, added the first two together, subtracted the next one,… Continue

Multiplication tables have some wonderful and quite surprising patterns. This is one of them. Draw any rectangle in a multiplication table and you will find… Continue

It was one of the most amazing visions of the future ever made. In 1965 Gordon Moore, one of the founders of Intel, proposed a… Continue

We have made a big deal of the times table and of other tables.Now we extend the times table to negative numbers and thus to… Continue

When Napoleon conquered Egypt in 1798 he went to the Great Pyramid of Giza. While his men climbed to its peak, he figured out that… Continue

Another famous pattern, Pascal’s triangle, is easy to construct and explore on spreadsheets. Create a formula for any cell that adds the two cells in… Continue

Picturing exponential growth, powers of 10, can be hard for any of us to imagine. The spreadsheet has the flexibility to enable us to explore the powers… Continue

The prime numbers are among the most fascinating objects in all of mathematics. While we can generate them, we do not know or understand their… Continue

We think about ratio tables in terms of motion. Move up 2 and over 1, or move up 1 and over 2. In this way… Continue

The rule of 72 is an old banker’s rule of thumb to find out how long it will take to double your money at different… Continue

Shapes introduces student to changing the colors in cells and to changing the shapes of cells by dragging the column or row separators in the… Continue

We take that great old problem of the inventor of chess and the ruler of India and use it to see how powers of 2… Continue

1, 3, 6, 10… are called the triangular numbers because they can be stacked up to form a triangle. They are very interesting numbers, and… Continue

Suppose Tom can paint the entire fence in twelve hours, and Huck takes eight hours. How long would it take the two of them together… Continue