Hi there fourth graders,
Remember we are about to start working with fractions, so the more time you use to reinforce the concepts of factors, multiples and practice working with decomposition the better. You really need to know this in order to begin with fractions.
We already had a quick look at Greatest Common Multiple (GCM) & Least Common Factor (LCF), also key topics to understand before jumping into fractions. Here you will find some links (Go to "Useful and Quite Interesting Links" section) to better understand and practice with these terms.