Teaching Fractions with Dominos

Looking for a tactile manipulative for helping students visualize fractions? Dominoes and fractions are natural partners:

1.             They both have two numbers.

2.             The numbers on both are separated by a line.

3.             Since the numbers are represented by dots, it’s a great visual for introducing fraction concepts.

4.             And the dominoes can be turned either way without a number becoming upside down.

Writing Fractions – For the beginning fractionier, have students select a domino and then turn it so it represents a fraction less than one.

Simplifying Fractions – Students select a domino, and then turn it so it represents a fraction less than one. To help them determine if the domino fraction can be simplified, have them redraw the domino on paper. Then ask them experiment to see if they can circle dots to create the same number of groups both above and below the fraction line. If they can, then the fraction can be simplified.

Improper Fractions – Select a domino and turn it so it represents an improper fraction. Once again, they can redraw the domino on paper to help them. Circle groups of dots in the numerator equal to the number of dots in the denominator. Count the circled groups to make the whole number. Uncircled denominator dots become the numerator.

Equivalent Fractions Game – Turn all the dominoes upside down. Two or more students all draw dominoes from the pile at the same time. As they turn them over, they try to find a pair of dominoes that are equivalent fractions. The first student to find a pair, wins the game. Turn the dominoes face down and play again.

Add, Subtract, Multiply, or Divide Fractions – Students select a pair of dominoes from the pile. Depending on their skill level, have them add, subtract, multiply, or divide the fractions represented by the dominoes.

Since domino sets come in double-sixes and double-twelve’s, the difficulty level of each of the above activities can easily be modified.

Oh, and don’t forget. In the original dominoes game, players match domino ends. They score when the sum of the end values is a multiple of five. Okay, so that doesn't have a lot to do with fractions, but it is, after all, dominoes.

(Previously Posted on my Adventures in Mathopolis blog, October 2011)

Techie Tips: Teaching Probability

I've used colorful candies, number cubes (aka dice), spinners, random number generators and more to hammer the concept of probability into my students’ heads. Apparently not an easy idea to grasp for most people, otherwise Vegas would go broke. Technology can provide teachers with many of the manipulatives mentioned above and more to help students conquer this concept.

Apps

Undecided, published by Deadmans Productions LLC is a free app. It includes a dice roller, coin toss, spinner, drawing for the short straw, rock/paper/scissors, and a random number generator.

Dice, published by Benoit Layer is also a free app. It allows you to customize it to roll anywhere from one to twenty dice at a time. The total for the dice rolled is shown in the background. Settings include dice color, sound, and background.

Websites

Marbles Probability (Shodor)

http://shodor.org/interactivate/activities/Marbles/

This site simulates the random selection of from 1 to 3 marbles from a bag. The chart shows all possible combinations, the percentage that a theoretical likelihood of a combination will be drawn, and the experimental outcome as a percent of each combination.

Adjustable Spinner (Shodor)

http://www.shodor.org/interactivate/activities/AdjustableSpinner/

The default spinner has four equal sections, but as the name implies, this can be adjusted. Just click and drag the slider next to each color, or type new percentages into the white boxes next to each.

Experimental Probability Spinner (Shodor)

http://shodor.org/interactivate/activities/ExpProbability/

As each color is spun, a tally is kept for each color. There are several pre-designed spinners or you can design your own spinner.

The Sum of Two Rolled Dice & Graphed Results (Saint Anne’s School)

http://www.saintannsny.org/depart/math/misterg.htm

This site will roll two six-sided dice and then graph the sum of the two dice. Click anywhere on the dice to begin, then press the space bar to roll the dice. The graph updates after each roll to reflect the sum of the two dice.

The Sum of Two Rolled Dice & Tallied Results (Shodor)

http://www.shodor.org/interactivate/activities/ExpProbability/

This site will roll two six-sided dice and tally the sum of the two dice in a chart. The dice rolls are displayed as a regular dice and as a net. You can also click the New Dice or Make Dice button to use a dice that repeats numbers.