The game is mainly for primary school grade four，corresponding knowledge point of the meaning and nature of decimal.The game is divided into two parts，The meaning of a decimal and the nature of a decimal.The first part the meaning of the decimal, by hand to form a decimal fraction, understand that there are several decimal 1/10, one percent, 1/1000. You need to use the box to show the meaning of the decimal. According to the number of decimal places, the game is divided into 6. A decimal 0.1-9.9 and 1; two decimal places 0.01-9.99 and 1; three decimal 0.001-9.999 and 1. The second part the nature of decimals. Two points. The first pass, simplified decimal. The balance beam at both ends of the board shows a decimal, double-click the number can be eliminated, the elimination of digital Jane decimal, correct balance to maintain the level of balance,small penguin cheering, wrong balance beam tilt, the penguins fall into the sea. Second pass, retain three decimal places or two decimal places. One end of the balance beam to display a decimal, the other end of the manual input to retain the results after the decimal, correct balance of the balance of the wood, wrong Penguin fell into the sea.Games of QD learn are developed specifically for primary school education ,both educative and entertaining.Game design is supported by educational theory.One game one knowledge point.Multi angle interpretation.Repeated practice of different forms of investigation.Play and learn focus.Master difficulty in interest.Proficiency test.QD learn aims at teaching through lively activities and happy learning.