Children usually start to learn about decimals in Year 4. The first thing children need to know is that a decimal is A PART of a whole. A good way to explain this is to show them an empty hundred number square / chart.
That still leaves the problem of memorizing a string of numbers, and here’s where the magic is. Teach children to skip count to the tune of a simple song. Have you ever wondered why children can learn the lyrics to songs so easily? It is because music can be used as a Mnemonic device, that is a strategy to assist with memorization. If you can associate the numbers with the sounds in a song, the children will not only learn them faster, but retain them much longer than they would memorizing them exclusively through repetition.