This video helps students to understand what the answer (quotient) and the remainder mean in the context of various word problems (where we need to use long division).
This is especially important when items are packaged into containers. When there are "leftovers" (a remainder), then those leftover items may need to go to a container also, though it will not be full.
The concept of average for 4th graders — video lesson
Math Mammoth Division 2 — a workbook with worksheets and lessons for long division, remainder, factors, and primes
Math Mammoth Grade 4 curriculum