Probability: Independent vs. Dependent Probability mass function of sum of two regular dice. (Photo credit: Wikipedia) Materials: Paper bag that you cannot see through 10 things of three colors, such as M&Ms, jelly beans, suckers, buttons, tiles Paper Pen or pencil Optional: change the number of colors or items Instructions: Draw a line across the paper. Above the line, write the name of each color Count the number of items of each color Just below the line, write down the number of items of that color Draw 10 lines below the color names and number them 1 through 10 Put all the items in... (Read More ...)

Fibonacci Sequence. The Fibonacci sequence in terms of rabbits (Photo credit: Wikipedia) The Fibonacci sequence is a series of numbers in which each number in the series equals the sum of the two numbers before it. It was described by Leonardo Fibonacci, an Italian mathematician, in his 1202 Book of Calculations. He also introduced and popularized Hindu-Arabic numerals, which he learned when he traveled with his merchant father to North Africa. They eventually replaced Roman numerals for calculations and that’s what we use today, the numbers 1, 2, 3, instead of I, II and III. The problem... (Read More ...)

A map of the USA demonstrating the four colour theorem. (Photo credit: Wikipedia) The Four-Color Theorem Normally, when you color in a pattern in a coloring book, you don’t pay attention to how many colors you need. You use as many crayons as you have available. But, what if you only had two or three or four crayons and you were asked not to let any color meet the same color at any edge, could you do it? Let’s see. Materials: 4 colors of crayons or colored pencils or pens Paper Straight edge Optional: Blank U.S. map Instructions: Draw a grid that is 3×3, that is a square, divided into... (Read More ...)

Magic Squares: Odd The magic square, according to Chinese legend, was first constructed on the back of a turtle and is called the Lo Shu magic square, the only order of numbers in a 3×3 grid in which they all add up to 15. The unique normal magic square of order 3, also known as the Lo Shu Square. (Photo credit: Wikipedia) By contrast, when there are 4 rows and columns, there are 880 different ways to lay out the numbers in a magic square. Constructing a magic square is different if there are an odd number of rows and columns than an even number. Let’s get started making your own! Materials: Paper Pen... (Read More ...)

Magic Square 4×4 (Photo credit: Wikipedia) Magic Squares: Even Do you know what a magic square is? It is a grid of numbers that add up to the same number whether you add up all the numbers across a row, or down a column, or diagonally. You can make your own. Let’s start with an even number of columns and rows in the square. We will make one with 4 rows and 4 columns, a grid design that is also described as 4×4 (four by four). Materials: Paper Pens or pencils Ruler or straight edge Instructions: Draw a grid that has four rows and four columns. Put numbers in each square of the grid,... (Read More ...)

Large Numbers There is a fable that the inventor of chess was rewarded by his king with whatever he wanted. A bowl of Cheerios (Photo credit: Wikipedia) Bowl of Cheerios Photo Credit Wikipedia He asked that a grain of wheat (or rice, depending on which fable-tellers you listen to) be placed on the first of the 64 squares on the chessboard and every day after that the number of grains of wheat doubled until all 64 squares were filled. The king readily agreed. After a week, the king’s accountant came to him and said, if you continue this path, we will be bankrupt. The king, however, honored his... (Read More ...)

Last week, readers spent the most time on: An aerial view of Mount Everest. (Photo credit: Wikipedia) How Do You Make a Strong Toothpick Bridge? Grandfather Poems. Funny. When Being a Grandma Isn’t So Grand Do Your Grandchildren Have a Different Religion Than Yours? Writing the Memoir Last month, readers spent the most time on: Popcorn and Crowds Who Taught You You Were Pretty? Who Invented the Computer Mouse? How Do You Make a Strong Toothpick Bridge? We’re Going to the Moon Coming up next week: Memorial Day, Monday, May 27, 2013 Roomie, Niagara Falls. Size 7. What Does... (Read More ...)

Scatter plot. As long as my grandson has been willing to play around with graphs recently, we have been trying to come up with more things to graph. A scatter plot with trend line of baby age to height. (Photo credit: Wikipedia) After we graphed the number of letters in state names and the size of states in area and population, we turned to rivers and created scatter plots. One of the things I found out in all this graphing activity is that you have to figure out how many lines you have available on your graph paper, in both directions, across the top and up the side. Then, find out the highest... (Read More ...)

Last week, readers spent the most time on: List of Star Wars air, aquatic, and ground vehicles (Photo credit: Wikipedia) Popcorn and Crowds Peas and Cheese Salad Do You Get Along with Your Grandchildren’s Other Grandparents? How Big Is Your State? Who Invented the Hula Hoop? Last month, readers spent the most time on: Grandparents. Poems. Funny. How To Do Nothing with Nobody What Are 10 Top Tips for a Long Marriage? Popcorn and Crowds Moore’s Law Coming up next week: Do You Like Tapioca? Monday, May 20, 2013 Moms. Desserts. House rules. Star Wars Tuesday, May 21, 2013 Lightsaber.... (Read More ...)

Ordering. Copyright catalogs at the Library of Congress. Located in room LM-404 of the James Madison Memorial Building, Washington DC. :The publication data for each magazine issue was hand-entered on the 3 by 5 inch index card. (Photo credit: Wikipedia) On a recent visit, my grandson asked me how big Virginia was. I asked him if he wanted to know the size in land or people. He said both. I got out 50 index cards. We wrote the name of one state on each card. We looked up the area, in square miles, for each state and wrote it on the index cards. Then, I asked him to lay out the index cards in... (Read More ...)