Subtracting Multiples of 10 Using Place Value

Khan Academy

This video provides a clear, step-by-step tutorial on subtracting multiples of 10 using place value concepts. The narrator walks through three specific examples, demonstrating how to simplify two-digit subtraction problems (like 90 - 60) by thinking of the numbers as groups of "tens" (9 tens - 6 tens). The video utilizes a digital whiteboard interface where numbers are typed into boxes as the logic is explained aloud. The key themes explored are place value, the relationship between addition and subtraction (inverse operations), and mental math strategies. The video explicitly connects the abstract concept of "90" to the concrete understanding of "9 tens," helping students bridge the gap between single-digit subtraction facts (9 - 6) and two-digit operations. It also touches on algebra foundations by using missing number boxes. For educators, this resource is an excellent tool for introducing or reinforcing First Grade Common Core standards regarding subtracting multiples of 10. It models a specific internal monologue students can use to solve problems mentally. Teachers can use this video to transition students from using physical manipulatives (like base-10 blocks) to abstract mental calculation, or as a remediation tool for students struggling with the magnitude of two-digit numbers.