Khan Academy
Khan Academy: Arithmetic and Pre Algebra: Level 2 Addition
A video explaining addition of a two-digit number and a one-digit number using the addition algorithm, objects and number lines. Practice problems are available. [9:47]
Khan Academy
Khan Academy: Subtracting Two Digit Numbers Without Regrouping (Example 2)
Sal subtracts two-digit numbers (without regrouping) by thinking about tens and ones. Includes a video, transcript, and question and answer section. [2:20]
CK-12 Foundation
Ck 12: Elem Math: Overview of Addition
[Free Registration/Login may be required to access all resource tools.] The video describes the two basic methods of adding numbers up to twenty. The methods shown are counting on and using tens and ones.
Math Mammoth
Math Mammoth: Add a 2 Digit Number and a 1 Digit Number Mentally: No Regrouping
Uses visual representations to model how to solve the addition of a 2-digit and a 1-digit number where there is no regrouping. [9:10]
Math Mammoth
Math Mammoth: Review: Adding and Subtracting Whole Tens
This video goes over how to add and subtract multiples of ten to or from a 2-digit number. [8:14]
Khan Academy
Khan Academy: Regrouping to Add 1 Digit Number
Demonstrates how to add 35 + 6 using drawings of base ten cubes to represent 1s and 10s and show the regrouping. [4:14]
Khan Academy
Khan Academy: Understand Place Value When Adding Ten
Demonstrates how to add two 2-digit numbers, with no regrouping, using drawings of base ten cubes to represent 1s and 10s. [3:16]
Khan Academy
Khan Academy: Teens as Sums With 10
The video looks at the 1 in each teen number and thinks about what it really means as representing 10, and the pattern of the teen numbers as ten plus some other number.
Math Mammoth
Math Mammoth: Naming and Writing Two Digit Numbers
In this lesson, students learn how to assign place value to two-digit numbers, how to write numbers as groups of tens and ones, and how to match place value to sets of dots. [5:13]
Math Mammoth
Math Mammoth: Add and Subtract Whole Tens
Teaches how to add and subtract multiples of ten. [5:07]
CK-12 Foundation
Ck 12: Elem Math: Overview of Addition Sums to 100
[Free Registration/Login may be required to access all resource tools.] The video explains two, two-digit addition problems one with regrouping and the other without regrouping.
Khan Academy
Khan Academy: Strategies for Adding 2 Digit Numbers
Watch as Sal goes through multiple strategies for adding 2-digit numbers. [3:15]