Mordkovich’s tasks often require a specific step-by-step methodology; seeing the "official" solution can help students understand the expected format for exams.
If you are studying from these books, you are likely working through: skachat gdz po matematika zubareva mordkovich
The Zubareva-Mordkovich curriculum is often considered more challenging than standard programs. It uses: decimal place values
Multi-digit operations, decimal place values, and basic geometry. and basic geometry.