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.
Learning multiplication facts is an essential part of childhood math. It takes time to learn them, but with a few tips and tricks, you can conquer them with practice. Once you have them memorized, you can work on getting faster with them so that the numbers just come to you. Some of the multiplication facts are simpler than others, but many of them have helpful hints that make them easier to learn.