Multiplying 4-Digit Numbers with Regrouping

MatholiaChannel

This video provides a clear, step-by-step demonstration of how to multiply a 4-digit number by a 1-digit number using the standard algorithm, supported by a visual place value chart. The lesson begins with a real-world word problem about calculating the total mass of three cars being transported on a truck. It introduces the concept using a bar model before moving into the calculation phase, making abstract arithmetic concrete for learners. The content focuses on the mechanical and conceptual process of multiplication with regrouping (carrying). It breaks the problem down into four distinct steps: multiplying the ones, tens, hundreds, and thousands. Crucially, it visually demonstrates the concept of "regrouping" using place value discs—showing how 15 ones become 1 ten and 5 ones, and how 22 tens become 2 hundreds and 2 tens. This dual representation helps bridge the gap between visual understanding and the written vertical method. For educators, this video is an excellent tool for introducing or reinforcing multi-digit multiplication. It is particularly useful for students who struggle with the concept of "carrying" numbers, as the side-by-side comparison of the written algorithm and the place value chart clearly explains where those extra numbers come from. The video supports standards related to place value understanding and properties of operations to perform multi-digit arithmetic.