Instructional Video
Khan Academy

Khan Academy: Understand Place Value When Adding Ten

1st - 2nd Standards
Demonstrates how to add two 2-digit numbers, with no regrouping, using drawings of base ten cubes to represent 1s and 10s. [3:16]
Instructional Video
Math Mammoth

Math Mammoth: Mental Addition of Two Digit Numbers

2nd - 3rd Standards
This video explains some strategies that are helpful for adding two-digit numbers in your head. [8:00]