In the 2nd-grade mathematics textbook by (School 2100 program), pages 4 and 5 of Part 1 focus on reviewing 1st-grade material, specifically "Numbers from 1 to 20" and basic operations. Page 4: Reviewing Numbers 1–20

Ensure you can explain why the answer is correct, as this is what teachers look for in class.

Usually involves a basic "increase by" or "decrease by" scenario.

Attempt the task on your own to strengthen your logic.

Solving equations or finding the unknown component in How to use GDZ (Reshebnik) effectively:

Page 5 transitions into solving simple word problems and expressions.

). For example, comparing the number of objects in two groups or simple numeric values like