Current research deals with students’ arithmetical and algebraical knowledge, with focus on a conceptual connection, and the relationship between two aspects of knowledge. The content in question is rational numbers, rational equations and problem-solving about proportion and ratio in grades 7, 8 and 9. The method contains three tests given to 400 students in grades 7–9. Tools for analysis were theories of generalizing arithmetic into algebra (Kieran, 2004) and the relationship between arithmetic and algebra in a conceptual context (Kaput, 2008). 

Current research shows that students’ knowledge of algebra and arithmetic often has a limited conceptual connection and a weak relationship. Their knowledge of arithmetic operations and solving rational equations use to be just procedural and rely on formulas learnt in a procedural way and often mixed up. The study also shows that students’ procedural strategies in finding formulas suitable for solving the equations, as well as carrying out the corresponding calculations, were often insufficient.  

The study pays attention to shortcomings in students' conceptualization of arithmetic operations with rational numbers and how to apply them solving rational equations. One reason for this is lack of continuity in instruction and learning.