Math Workbook with Examples. Math Trainer. ADDING AND SUBTRACTING WITHIN 20

The trainer contains 800 examples of addition and subtraction within 20. With its help, the child will automate the skill of mental arithmetic, including regrouping, and gain confidence in their abilities. The tasks were developed by a primary school teacher with many years of experience. The trainer will be useful for preschoolers and students in grades 1-2.