Our Determining Unknown Numbers lesson plan teaches students problem-solving skills that can be used to find missing or unknown numbers in addition or subtraction equations. Students are asked to play an interactive game with a partner in which they hide cotton balls under a cup and the other students has to count the remaining cotton balls to determine the number under the cup. Students are also asked to complete practice addition and subtraction problems on their own using the strategies learned in this lesson.
At the end of the lesson, students will be able to determine an unknown number in an addition or subtraction equation.
Common Core State Standards: CCSS.Math.Content.1.OA.D.8, CCSS.Math.Content.2.OA.A.1