The common-core math standards require that students learn the standard algorithm ... students were introduced to the algorithm for multi-digit addition and subtraction in 2nd grade.

Now, he solves for an unknown in any position. This video addresses Common Core Grade 2 Standard Operations & Algebraic Thinking: Represent and solve problems involving addition and subtraction.

In the CCSS, it’s actually referred to as the “standard algorithm” for addition and subtraction, and the CCSS require that students completely master it for multi-digit numbers by the end of ...

Common Core still requires students to learn and understand the standard algorithm ... representation of what subtraction is: figuring out the “distance” between two numbers.