Big Idea:Students can perform addition and subtraction within 100 using a variety of math tools, however, determining which operation to use is a higher level thinking skill that is being introduced in this lesson.
Big Idea:Common Core standards encourage the use of models to build understanding in math. This lesson shows sometimes reluctant 2nd graders that models are helpful tools in solving mathematical problems.
Big Idea:Students are able to add and subtract when numbers are presented horizontally. They add and subtract tens and ones with appropriate fluency. Today they will be introduced to adding two 2-digit numbers presented vertically.
Big Idea:In part 1, students all were able to add two numbers presented vertically and relate each 2-digit number to the nearest 10. Today I need to check for understanding verses the rote application of the process.