If you're seeing this message, it means we're having trouble loading external resources on our website.

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

### Course: 6th grade>Unit 7

Lesson 3: One-step addition & subtraction equations

# One-step addition & subtraction equations: fractions & decimals

In this math lesson, we practice solving equations with variables and fractions. We learn to isolate the variable by adding or subtracting terms from both sides of the equation. This helps us find the value of the variable, making the equation true. Keep practicing and have fun!

## Want to join the conversation?

• This video is good and all, but what if the denominator of the fractions are not the same. Then what do I do then, please explain. Cause I have a problem that doesn't have the same denominator.
• You still move the fraction away from the side with the variable. Then to do the addition/subtraction on the other side, you will need to use the correct steps for adding & subtracting fractions:
1) find a common denominator
2) convert each fraction to the common denominator
3) then, add/subtract the fractions.

If you look at the other questions posted under this video, you will see some examples of problems with different denominators.

Hope this helps.
• distance maybe?
• check again your answer maybe not write though
(1 vote)
• Does Sal ever get anything wrong?
• Yes - Sal is human. If you watch the videos in regular mode (not full screen), then you will see correction boxes that pop up to correct content in the video.
• Ill give you one to solve. 35= x/7
• You have "x divided by 7" on the right side. To move the 7, you use the opposite operation to division. You need to multiply both sides by 7.
See if you can finish the problem.
Hope this helps.
• What if the denominators are different like 11/6=n+7/9?

Thank you! :3
• If you have X+5=13 you could just subtract 5 from 13 instead of adding or subtracting something to both sides.
• You are just skipping work steps. The property that lets you do what you are suggesting says that you must add/subtract the same value from both sides. You are just skipping the step of writing out that +5-5 = 0 on the left side, which is what makes the 5 disappear on that side.
• what if it's 1/8+c=4/5?
• You would subtract 1/8 from both sides. And, to do the 4/5-1/8 you follow the rules for working with fractions. You need to convert to a common denominator before subtracting.
• How to add and subtract when the fractions have different denominators and numerators?
• The best thing for you to do is to review the lessons on Fractions in the Arithmetic course here on KhanAcademy.
• This video is good and when i see this video i got little easy