Adding to 10 is but on example of a large number of spreadsheets that could be developed to practice addition. We give students two number… Continue

Multiplication is often thought of as repeated addition. By building a times table by using a repeated addition rule you will have a fun practice… Continue

Now that students can build addition tables, they should look for the patterns in them. We introduce them to a variety of things they might… Continue

We have been using cell addresses informally until now, but now we can be more formal and explicit. Different spreadsheets have different types of address… Continue

Parentheses are not only important in paper math, they are critical in spreadsheets. To make sure that terms are handled properly by spreadsheets, we have… Continue

Spreadsheets can be a great place for you to build your own games. Ryan has built one of his early favorites, Battleship, where you learn… Continue

Students are tasked to build a times table in just two steps. They have to learn to use absolute as well as relative addressing to… Continue

We can use these proportions to compare two ratios with different denominators by finding a denominator that their proportions have in common. Thus the common… Continue

The symmetry of the multiplication table around the square numbers diagonal we call commutativity or the commutative property. It means that in a 12 by… 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 Multiplication 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

We can make a division table just like we made a multiplication table. Division is surprisingly our most important operation in terms of most of… Continue

Though spreadsheets lets you put geometric shapes on the screen, those shapes are not connected with the cells and cannot be changed by using different… Continue

Spreadsheets are great for creating secret codes and for breaking them. During World War II the German military used a machine they called Enigma to… Continue

Spreadsheets always automatically perform the operations you ask them to do. But sometimes we want to see the process. We can make spreadsheets show us… Continue

Graphs as we know them were first invented by Galileo. They are powerful images of functions. I will introduce you to graphs by letting you… Continue

How many of the numbers from 1 to 100 are in the times table? All, Most, Less than half? I think you will find in… Continue

What if you built a rule that would enable you to count backwards? How would it be the opposite of addition? What would happen if… 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

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

Spreadsheet math generally focuses on ratio and proportion to develop the concept of fraction. But fractions is such a big problem in today’s curriculum that… Continue

We use rules to build new numberlines. For example we can start in the middle and go both forward or backward using adding and subtracting rules. You can even… Continue

George is in New York and Martha is in Washington. They leave at the same time and follow the same road to meet each other… Continue

Number Lines introduce students to functional thinking and the use of formulas in spreadsheets. For younger students we call these formulas “rules” and ask students… Continue

Use numberlines and spreadsheet rules to explore the amazing patterns we find in our whole numbers. Did you know that you can get the odd… Continue

Spreadsheets make it easy for us to explore patterns in the whole numbers. This Lab does that and helps you learn the basics of spreadsheets… Continue

Pennies to Heaven is a Fermi Problem, basically a “headmath” experiment. Fermi Problems, originally developed by Enrico Fermi, one of the greatest experimental and theoretical… Continue

Our number system inherited from India and from the Medieval Arab world enables us to use just 10 symbols to write any number we can… Continue

We take our place value generator to decimals to help students see the simplicity of the place value pattern going right as well as left. 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

Using the times table, students can see that products are always rectangles, and that they represent the area of that rectangle. They should explore the… Continue

We use the hundreds table to introduce rows and columns and focus students on seeing the patterns in these tables. Again and again we go… Continue

The square numbers form an interesting pattern on the times (multiplication) table. They run along a diagonal from 1 to the top right of the… Continue

What would a subtraction table look like? How would its pattern be different from an addition or multiplication table? Is subtraction commutative? Continue

Have you ever played Sudoku? It is fun and challenging. You have to find the numbers from 1 to 9 in each cell so that… 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