The notebook for extracurricular work in mathematics with the students from the second and third grade is a supplement to the MATHEMATICAL PRIMER FOR 2-3. CLASS and contains 28 topics with over 180 tasks. Sample solution models have been proposed for some of them. These models are not the only options for solutions and do not need to be memorized by children. These are just examples of this is short and clear, but it is reasonable and comprehensive to present the solution. The notebook aims to teach second and third graders to write when solving problems. It is desirable for teachers and parents to confirm the children in order to find their own solutions, which they can present in writing.