**Freudenthal Ins****ti****tute**, Utrecht University develops applets to support teaching and learning of mathematics and science. Using the applets need internet connection and java support. The applets are categorized based on the grades/ groups and topics. Problem solving is a part of these applets. Students may be challenged to solve it. The advantages of using applets are:

**More interesting**

It is more colourful and attractive. These can motivate students to work with problems. They will put interest on the problems because they can play with it. Sometimes, they are not afraid of making mistakes.

**Adaptable Pace**

Mostly, students can replay or undo or restart again to solve the problems. The challenge can be more fun than when it uses applets because it is wrapped creatively.

**More efficient and Reusable**

To some extents, working with concrete manipulative is different with working with virtual manipulative or applets. Concrete manipulative using paper will not last longer. If it involves cutting and gluing, then it is not reusable. Using virtual manipulative or applets can be used many times and reusable as long as the devices support it. Language can be an obstacle, but students often play games in without knowing the languages used.

**Examples**

To see how challenging the applet, we may try this problem/task to our students. Some problems can be accessed in http://www.fisme.science.uu.nl/toepassingen/03252/opdracht2.html. The aim of this activity is to lay down the planks into the provided space. Therefore, students have to the empty square is 7×7. Teachers may use concrete materials to let students deal with this task. However, creating the concrete material can be a problem for teachers. It is possible that they are lack of _me and money. Therefore, applets help teachers deal with this problem. It is ready to use and easy to access. Working with the task is quite challenging for students. They may work in pairs or groups. Students may have different solutions and some students may see this difficult. However, when they failed, they can restart again by dragging out the planks. The teacher may look around and keep students on track. Let student present their work or solutions. To assess students understanding, we can let them show how they get the solutions. They should explain how different solutions are acceptable. They also should explain what kind of mathematical ideas behind it. As homework, students may try the following Problem.