Perhaps discuss with the students in plenary when this skill is required in the real world? Odometers use base ten in the car, see if you can find an interactive one online. Linear measurement, converting from mm to cm using this skill. Try a web search on understanding base ten concepts and virtual manipulatives for some ideas you could translate into an investigation. I had a year six class last year and one of the problems we encountered when working with decimals they sometimes forgot that the decimal point does not occupy a place on it's own but is always stuck to the "ones or units" column. This meant that when they were asked to identify the value of a number in a nominated column they sometimes got the tenths, hundredths etc out by a factor of ten as they had started with thinking the tenths column was a corresponding version of a units column. So basically they needed to understand that the symmetry was based around the units column and then counting out each side was ten, tenths, hundreds, hundredths etc. Some ESL students needed support with the vocabulary and hearing the difference in the words/spelling. Others in the pre assessment task had reversed the order of the tenths hundredths columns. sigh... I like to focus on them getting a feeling for what the size of the numbers they are dealing with and try at all costs not to simply teach the trick of moving the decimal point one place to the left or right. In fact there is a bit of online debate around about that concept. It is not the decimal point that is moving, they should think of it as staying in the same place and the numbers are what are being exchanged, go back to the odometer analogy. Everything will depend on the where you are in the unit at the moment and the ability of each student as to how secure they are with the concept of the base ten number system. Google some base ten games perhaps. It is my experience with supervisor visits thought that it is worth making sure the basic concepts are really sound (from your perspective) before getting off into games and whizzy bang stuff that may not come off well if they kids are thrown into it and it is not how they usually work in maths sessions.