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 this lesson, students put all of their addition and subtraction skills together to solve equations. Julia begins with a Number of the Day warm up activity, followed by practicing 2 and 3 ...

Add 2-digit numbers ... subtracting a one-digit number from a three-digit number. How to add and subtract in your head Explore how to use mental methods for addition and subtraction.

It looks different, but it still has two parts ... Just like with addition, we can use a part-whole model to help partition larger numbers to make them easier to deal with in subtraction problems.