I can walk you through the math for any of them!
Websites like Znania or Uchi.ru allow you to type in the specific text of a word problem from Lesson 43 to see the full reasoning. onlajn gdz 4 klass pervoe polugodie gejdman urok 43 otvety
For visual learners, there are creators who go through the Geidman curriculum page-by-page. You can often find these by searching "Гейдман 4 класс урок 43" on platforms like YouTube or Rutube. I can walk you through the math for any of them
A store received 856 textbooks. They sold some, and of the sold amount remained. The Math: If 856 books were sold, the remainder is the remainder is