Decomposing 18 into Tens and Ones with Monkeys

Khan Academy

This educational video introduces young students to the concepts of addition and place value through a whimsical word problem involving a party of monkeys. The narrator presents a scenario where a student has 10 monkeys but needs 18 for a party, challenging viewers to determine how many more are needed. Rather than simply counting up, the video breaks down the number 18 conceptually, explaining the significance of the tens and ones places to show that 18 is composed of one group of ten and eight ones. The content focuses on key mathematics themes including decomposing teen numbers, understanding place value, and solving "how many more" addition problems. By visualizing the number 18 as "10 + 8," the video helps bridge the gap between concrete counting and abstract algebraic thinking. It uses clear visual aids—purple monkey faces—to represent the quantities, making the math tangible for early learners. For classroom application, this video is an excellent resource for Kindergarten and 1st Grade math lessons. It effectively demonstrates how to use known quantities (a group of 10) to find unknown variables. Teachers can use this to introduce base-ten concepts, reinforce the structure of teen numbers, or practice addition strategies that rely on making a ten. The engaging narrative offers a fun hook for math centers or whole-group instruction.