### Numeracy

- Parentheses are not only important in paper math, they are critical in spreadsheets. To make sure that terms are handled…Read more
- The symmetry of the multiplication table around the square numbers diagonal we call commutativity or the commutative property. It means…Read more
- The distributive property turns out to be central to a surprising variety of important mathematics. One of the most valuable…Read more
- We introduce students to more complex patterns and rules in hundreds tables. In particular, we have students look at diagonal…Read more
- This is one of those math puzzles that come up in contests but which turn out to be quite interesting…Read more
- We use rules to build new numberlines. For example we can start in the middle and go both forward or backward using adding…Read more
- Our number system inherited from India and from the Medieval Arab world enables us to use just 10 symbols to…Read more
- Using the times table, students can see that products are always rectangles, and that they represent the area of that…Read more
- Multiplication tables have some wonderful and quite surprising patterns. This is one of them. Draw any rectangle in a multiplication…Read more
- Pennies to Heaven is a Fermi Problem, basically a “headmath” experiment. Fermi Problems, originally developed by Enrico Fermi, one of…Read more
- We take our place value generator to decimals to help students see the simplicity of the place value pattern going…Read more
- We extend the place value generator to 100’s of thousands to show you how the pattern of 1’s, 10’s, 100’s,…Read more
- Spreadsheet math generally focuses on ratio and proportion to develop the concept of fraction. But fractions is such a big…Read more
- Use numberlines and spreadsheet rules to explore the amazing patterns we find in our whole numbers. Did you know that…Read more
- Spreadsheets make it easy for us to explore patterns in the whole numbers. This Lab does that and helps you…Read more
- The prime numbers are among the most fascinating objects in all of mathematics. While we can generate them, we do…Read more
- I built a Lab for you to play with the Syracuse Problem and to learn to use spreadsheets to play…Read more
- What would a subtraction table look like? How would its pattern be different from an addition or multiplication table? Is…Read more
- Have you ever played Sudoku? It is fun and challenging. You have to find the numbers from 1 to 9…Read more
- Spreadsheets are great for creating secret codes and for breaking them. During World War II the German military used a…Read more
- 1, 3, 6, 10... are called the triangular numbers because they can be stacked up to form a triangle. They…Read more
- Fibonacci, the nickname given the great medieval mathematician Leonardo of Pisa, is connected in most of our minds with the…Read more
- In introducing Spreadsheets we want you to learn to build a numberline by using a rule (a formula). We begin with a…Read more
- Number Lines introduce students to functional thinking and the use of formulas in spreadsheets. For younger students we call these…Read more
- This is the graduation exercise for the basic use of spreadsheets. We combine rules and addressing to have students build…Read more

### Addition/Subtraction

- Adding to 10 is but on example of a large number of spreadsheets that could be developed to practice addition.…Read more
- Now that students can build addition tables, they should look for the patterns in them. We introduce them to a…Read more
- From here on students can go in most any order they choose. They can start with addition or with multiplication.…Read more
- Spreadsheets with their natural grid make a great, though not entirely flexible, platform for architectural design and for working with…Read more
- We use rules to build new numberlines. For example we can start in the middle and go both forward or backward using adding…Read more
- Multiplication is often thought of as repeated addition. By building a times table by using a repeated addition rule you…Read more
- Decimal addition is one of a series of Labs to help you understand and learn to use decimals. I think…Read more
- Decimal subtraction is one of a series of Labs to help you understand and learn to use decimals. I think…Read more
- Use numberlines and spreadsheet rules to explore the amazing patterns we find in our whole numbers. Did you know that…Read more
- What would a subtraction table look like? How would its pattern be different from an addition or multiplication table? Is…Read more
- Have you ever played Sudoku? It is fun and challenging. You have to find the numbers from 1 to 9…Read more
- 1, 3, 6, 10... are called the triangular numbers because they can be stacked up to form a triangle. They…Read more
- This is the graduation exercise for the basic use of spreadsheets. We combine rules and addressing to have students build…Read more
- George is in New York and Martha is in Washington. They leave at the same time and follow the same…Read more
- What if you built a rule that would enable you to count backwards? How would it be the opposite of…Read more

### Multiply/Divide

- Counting-By introduces multiplication. Counting-by or skip-counting is, we believe, the best way to help students build their multiplication facts, and…Read more
- The distributive property turns out to be central to a surprising variety of important mathematics. One of the most valuable…Read more
- Multiplying creates products, factoring separates a product into the numbers that make it up. We thus start with the table…Read more
- Spreadsheets always automatically perform the operations you ask them to do. But sometimes we want to see the process. We…Read more
- This is one of those math puzzles that come up in contests but which turn out to be quite interesting…Read more
- Using the times table, students can see that products are always rectangles, and that they represent the area of that…Read more
- Multiplication tables have some wonderful and quite surprising patterns. This is one of them. Draw any rectangle in a multiplication…Read more
- The square numbers form an interesting pattern on the times (multiplication) table. They run along a diagonal from 1 to…Read more
- We can make a division table just like we made a multiplication table. Spreadsheets will usually turn such tables into…Read more
- We can use these proportions to compare two ratios with different denominators by finding a denominator that their proportions have…Read more
- Pennies to Heaven is a Fermi Problem, basically a “headmath” experiment. Fermi Problems, originally developed by Enrico Fermi, one of…Read more
- We take that great old problem of the inventor of chess and the ruler of India and use it to…Read more
- We have made a big deal of the times table and of other tables.Now we extend the times table to…Read more
- Decimal Division is one of a series of Labs to help you understand and learn to use decimals. I think…Read more
- Decimal Multiplication is one of a series of Labs to help you understand and learn to use decimals. I think…Read more
- The prime numbers are among the most fascinating objects in all of mathematics. While we can generate them, we do…Read more
- I built a Lab for you to play with the Syracuse Problem and to learn to use spreadsheets to play…Read more
- How many of the numbers from 1 to 100 are in the times table? All, Most, Less than half? I…Read more
- How many of the products in a 12 by 12 times table are odd numbers? This is a question we…Read more
- Students are tasked to build a times table in just two steps. They have to learn to use absolute as…Read more

### Powers/Roots

- This is one of those math puzzles that come up in contests but which turn out to be quite interesting…Read more
- Another famous pattern, Pascal’s triangle, is easy to construct and explore on spreadsheets. Create a formula for any cell that…Read more
- Spreadsheets offer us a nearly unlimited ability to develop and learn from case studies using real world data. We will…Read more
- We look at world population over the past 60+ years and ask whether the earth’s population is growing faster or…Read more
- We take that great old problem of the inventor of chess and the ruler of India and use it to…Read more
- The rule of 72 is an old banker’s rule of thumb to find out how long it will take to…Read more
- 1, 3, 6, 10... are called the triangular numbers because they can be stacked up to form a triangle. They…Read more
- It was one of the most amazing visions of the future ever made. In 1965 Gordon Moore, one of the…Read more
- Picturing exponential growth, powers of 10, can be hard for any of us to imagine. The spreadsheet has the flexibility…Read more

### Ratio

- Shapes introduces student to changing the colors in cells and to changing the shapes of cells by dragging the column…Read more
- Multiplication tables have some wonderful and quite surprising patterns. This is one of them. Draw any rectangle in a multiplication…Read more
- The square numbers form an interesting pattern on the times (multiplication) table. They run along a diagonal from 1 to…Read more
- We can make a division table just like we made a multiplication table. Spreadsheets will usually turn such tables into…Read more
- We think about ratio tables in terms of motion. Move up 2 and over 1, or move up 1 and…Read more
- Ratios can be written in a wide variety of different way: as fractions, as decimals, and as percents.,with a colon,…Read more
- We take that great old problem of the inventor of chess and the ruler of India and use it to…Read more
- There are a wide variety of financial literacy problems. This is the kind of problem that appears on many tests.…Read more
- Manage a business. The Lemonade Stand has been a business simulation developed in many different versions. We believe this is the…Read more
- How much are your credit cards costing you? If you are like most of us, they are very expensive because…Read more
- Create, manipulate, and explore triangles in this live interactive spreadsheet. On the surface, a triangle is being drawn on a…Read more
- Which form of interest, simple or compound, is the fairest? If you were buying a house or a car which…Read more
- Fibonacci, the nickname given the great medieval mathematician Leonardo of Pisa, is connected in most of our minds with the…Read more
- Picturing exponential growth, powers of 10, can be hard for any of us to imagine. The spreadsheet has the flexibility…Read more
- This chart recently came out from the American Lung Association about air pollution in the United States. How would you…Read more
- In a class of 23 students, the chances are fifty-fifty that two of them will have the same birthday. Now…Read more
- Fractions are ratios that's why we call them rational numbers (ratio numbers). If you think about fractions as ratios, how…Read more
- How many gallons of a 70% alcohol solution must be added to 30 gallons of a 10% alcohol solution in…Read more
- When Napoleon conquered Egypt in 1798 he went to the Great Pyramid of Giza. While his men climbed to its…Read more
- Suppose Tom can paint the entire fence in twelve hours, and Huck takes eight hours. How long would it take…Read more