Visualizing Addition Using Base Ten Blocks

Khan Academy

This video provides a clear, visual demonstration of adding two-digit numbers (23 + 45) without regrouping, using digital base-ten blocks. The narrator systematically breaks down each number into its constituent parts—tens represented by gold vertical bars and ones represented by small blue squares—to visually illustrate the concept of place value. By counting the blocks explicitly, the video bridges the gap between concrete physical quantities and abstract numerical digits. The core themes explored are place value (tens and ones), number decomposition, and the standard algorithm for vertical addition. The video emphasizes that the digit in the tens place represents groups of ten, while the digit in the ones place represents single units. It visually validates the standard addition method by physically combining the groups of 'ones' first, followed by the groups of 'tens', showing that the vertical alignment of digits corresponds to combining like terms. For educators, this video is an excellent tool for introducing or reinforcing multi-digit addition in early elementary classrooms. It serves as a perfect transition from working with physical manipulatives to writing equations. Teachers can use this to demonstrate 'why' we line up numbers vertically and to correct the misconception that digits in different columns have the same value. It supports visual learners by providing a concrete model for the abstract process of arithmetic.