Khan Academy: Arithmetic and Pre Algebra: Adding Fractions With Different Signs

This video shows how to add positive and negative money amounts in the context of a word problem using a number line. Practice problems are available. [3:15]

This video introduces and demonstrates the concept of addition of integers using a number line. Practice problems are available. [5:32]

This video shows how to plot fractions, negative numbers, decimals, and fractions on a number line. Practice problems are available. [1:58]

A video explaining the meaning of exponents and exponential notation. Practice problems are available. [9:46]

This video introduces and explains the concept of ratios through a number of examples. Practice problems are available. [14:13]

This video demonstrates how to find the base number when given a percentage and amount. Practice problems are available. [6:17]

This video shows how to find a unit rate in the context of a word problem. Practice problems are available. [2:31]

This video explains how to convert a repeating decimal with more than one repeating digit to a fraction. Practice problems are available. [9:05]

This video showing more examples of long division problems involving single-digit divisors with remainders. Practice problems are available. [10:07]

This video teaches addition and subtraction of negative numbers using a number line. Practice problems are available. [9:16]