Counting Large Numbers by Grouping into Tens and Ones

Khan Academy

This educational video provides a clear, visual demonstration of the fundamental mathematical concept of place value, specifically focusing on the tens and ones places. Using a long bar composed of individual green segments, the narrator breaks down a large unknown quantity into manageable groups of ten. This process illustrates the efficiency of our base-10 number system, transforming a long string of units into a structured representation of '4 tens' and '2 ones'. The video explores key themes of counting, grouping, and the relationship between concrete quantities and abstract digits. By physically boxing off groups of ten on screen, the narrator makes the transition from counting by ones to counting by tens explicit and visual. The lesson culminates in constructing the number 42, explaining that the digit '4' represents four groups of ten (40) and the digit '2' represents two single units, connecting the standard numeral to its expanded form (40 + 2). For educators, this video serves as an excellent introduction or reinforcement tool for teaching number sense and place value in early elementary grades. It bridges the gap between rote counting and understanding the structural meaning of two-digit numbers. Teachers can use this video to model how to group objects for easier counting, introduce the concept of digits having different values based on their position, and demonstrate the connection between visual models and written numerals.