Subtracting Within 20: Finding the Difference Between Two Numbers

This video is a math lesson that teaches how to subtract within 20 by finding the difference between two given numbers. The video starts by reviewing the definition of subtraction and explaining how subtraction is related to addition through fact families. The lesson also provides examples of using an open number line to add up and find the difference between the two numbers. Additionally, the video demonstrates how to count up from the smaller number to find the difference.