In this lesson, students will learn the steps involved in computational thinking.  Decomposition, pattern matching, abstraction, and algorithms are all steps that make up the computational thinking process. This process is used in many learning subjects and in real-life learning.  Learners discover how understanding each step can help them as a learner and also nurture a growth mindset.

According to Achieve the Core, (achievethecore.org), "The joint purpose of this task is to provide students an opportunity to practice two-digit subtraction with regrouping and to engage students in looking for and expressing regularity in repeated reasoning (MP.8). Throughout grade 2, students need many opportunities to practice subtraction in order to achieve fluency subtracting within 100 by the end of the grade. For students in grade 2, it is sufficient for them to recognize that differences of 9 will stem from numbers whose digits differ by 1, subtractions resulting in 18 will stem from numbers whose digits differ by 2, etc. "

Students will begin to improve their computational fluency with combinations of 10, 15, and/or 20. They will develop strategies for combining numbers as they solve problems and play games. They will be able to apply their knowledge of these basic facts to word problems and more complicated computational problems. They will begin to use the commutative property and realize that in an addition problem the order of the numbers does not matter.