Khan Academy: Arithmetic and Pre Algebra: Basic 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]

This video covers a short review of addition, followed by basic subtraction concepts. Practice problems are available. [8:32]

This video provides an overview of subtraction. Practice problems are available. [12:32]

This video shows how to round a 4-digit number to the nearest ten. Practice problems are available. [1:04]

This video explains the commutative law of addition. Practice problems are available. [1:40]

In this exercise, students practice breaking apart two-digit addition problems. Students receive immediate feedback and have the opportunity to get hints and try questions repeatedly.

Sal solves addition and subtraction equations with number 10 or less. Includes a video, transcript, and question and answer section.

Sal demonstrates the relationship between addition and subtraction using objects. Includes a video, transcript, and question and answer section. [2:05]

Sal solves 1 addition and 1 subtraction word problem involving superheroes and sea monsters. Includes a video, transcript, and question and answer section. [3:37]

Sal solves addition and subtraction word problems involving exercising gorillas and cookies. Includes a video, transcript, and question and answer section. [5:31]