If you're seeing this message, it means we're having trouble loading external resources for Khan Academy.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Adding and subtracting rational numbers

3 videos
1 skill
We're going to mix it up a little in this set of examples. Remember that a rational number is a real number that can be written as a simple fraction, or by extension a decimal or percentage. We have to be able to add and subtract numbers when they are in different formats, whether fraction, decimal or percentage. This gets to be fun as learn to move between these expressions of rational numbers, and start to understand they're all pointing to same thing! Common Core Standards: 7.NS.A.1d

Adding, subtracting numbers in different formats

VIDEO 4:29 minutes
In this example, we solve an addition problem with numbers in different formats: a percentage, decimal, and mixed number. First, we'll get them all in the same format...which makes it a while easier to solve!

Adding, subtracting fractions, decimals, percentages

VIDEO 4:34 minutes
What happens when we are asked to add or subtract fractions, decimals, and percentages? You'll see in this example that we first get them in the same format, and then add fractions.

Adding, subtracting fractions

VIDEO 2:36 minutes
Our focus here is on learning to multiply fractions. First we have to get the common denominator, then add positive and negative numbers.