urff.app

Dezimat

The Dezimat is an interactive visual aid to deepen and explore the understanding of decimal fractions.

‎Dezimat
‎Dezimat
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‎Dezimat
Developers: Christian Urff
Price: 0,99 €
functions

The Dezimat is a way of visualizing decimal numbers and their place values. In addition, the following visualizations are available, which can be shown or hidden:

  • number line: Displays a number line to visualize the range of decimal numbers between 0 and 1. The number line can be moved and you can also zoom in and out of the number line using two fingers.
  • fractions: Display the display of fractions for a better understanding of the decimal place values.
  • place value table: Visualizes the place values of numbers for a better understanding of decimal numbers. This representation can also display non-canonical representations. This means that places can be filled with numbers greater than 9
  • decimal numbers: Displays decimal numbers up to ten thousandths.

In addition to a experimental environment with synchronized presentations to try out and discover independently, as well as some exercises and games in the practice area.

Notes on didactic embedding

The app can be used after an introduction with paper and pens for further in-depth discovery and practice. Materials based on AMSI Calculate are available in English.

Example tasks

for the experimental environment

  • Represent the number 0.2456
  • Convert the decimal number 0.75 into a fraction. Then check whether you have converted correctly by displaying the fraction representation.
  • Arrange the following dacimal numbers according to their size and justify using the decimal: 0.0256 0.2560 0.5602 0.2056
  • You have 7 tenths, 12 hundredths and 2 ten thousandths. What decimal number is that?
  • Bundle 125 cent-thousandths on the decimat to get the largest possible number of hundreds.
  • Use the decimal point to form the largest / smallest decimal number possible from the numbers 5, 8, 1 and 6.
  • Describe the meaning of a number in different places, for example: 0.5 with 0.05 with 0.005. What do you notice?
Subject didactic background

The representation of decimals as a decimat is a learning tool to promote the understanding of decimal fractions and their place values and is based on the idea of Roche (2010). The visualization serves to reduce common misconceptions about decimals by visually representing the concept of the "tenth" of our decimal place value system. For example, a study by Steinle and Stacey (2004) found that many students have difficulty understanding the size of decimal numbers such as 0.97, which subsequently leads to basic errors in mathematical operations based on decimals. The representation as a decimat is intended to address this understanding problem by offering a proportionally scaled model that makes decimal fractions clear.

The Decimat can not only help students to intuitively grasp the size of decimals such as "almost one" for 0.97, but also encourages the use of fractional language to describe decimals. Using the tool in playful activities, such as the partner game, allows children and young people to gain a deeper understanding of the relationships between tenths, hundredths, thousandths and ten thousandths.

The app is recommended as a complement to other materials to introduce basic concepts of decimal notation and decimal fractions in grades 4 to 7. However, the app can also be easily adapted (for example, by only considering tenths or hundredths) to be used with younger students. It is important to use the app regularly and with appropriate introduction and support in well-structured learning environments to use.

conception and development

This app was developed by Christian Urff in collaboration with Dr. Axel Schulz (University of Bielefeld) and JProf. Dr. Daniel Walter (University of Dortmund).

Sources
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