Recently a team of third- and fourth-grade teachers tested instructional ideas on the topic of division with remainders (DWR) using lesson study. The Common Core State Standards for Mathematics give little attention to the concept of the remainder, specifying only that students are to solve problems for which remainders must be interpreted (NGA…

In science classes, students usually learn about the law of definite proportions by the oxidation of copper. However, common procedures usually do not lead to proper results. This leads to confusion among the students because their experimental results do not fit to the theoretical values. Therefore, we invented a new procedure for this experiment…