   # Practice addition and subtraction of fractions

Adding and subtracting fractions can be time consuming because it often involves a few extra steps. This is a really important and commonly used skill, though. To add or subtract fractions:

• Find the lowest common multiple of the denominators.
• Express all fractions in terms of the lowest common denominator.  # Basic addition and subtraction of fractions, no LCM required

Basic addition and subtraction of fractions without LCM students usually learn in 3rd, 4th grade. This activity allow to master these skills.  # Advanced addition and subtraction of fractions, LCM required

Advanced addition and subtraction of fractions requires finding the LCM of the denominators. It is important for the students to master this skill.

## Progress report

The report shows the learning progress in percentage (0% - not learned, 100% - learned perfectly).
There are three levels of the report.

### Short report

Add, subtract with 1 and 1/2: 90%
Add and subtract fractions with different denominators, no LCM: 71%
Add and subtract fractions, LCM required: 94%

### Normal report

Add, subtract with 1 and 1/2
Subtract from 190%
Subtract from 1/280%
Add, subtract fractions with different denominators,
no LCM
Add fractions (no LCM)70%
Subtract fractions (no LCM)72%

Add and subtract fractions,
need to find LCM
 a k
±
 b 2k
82%
 a k
±
 b 3k
85%
 a k
±
 b 4k
77%
 a k
±
 b 5k
74%
 a 2k
±
 b 3k
70%
 a 2k
±
 b 5k
41%
 a 2k
±
 b 7k
29%
 a 3k
±
 b 4k
27%
 a 3k
±
 b 5k
26%

### Detail report

Addition and subtraction of fractions with 1 and 1/2.

Subtract from 1 90% 80% 100%

Addition of fractions with different denominators, no LCM.

 a k
+
 b 2k
60%
 a k
+
 b 3k
80%
 a k
+
 b 4k
80%
 a k
+
 b 5k
20%
 a k
+
 b 6k
40%
 a k
+
 b 7k
80%
 a k
+
 b 8k
100%
 a k
+
 b 9k
100%
 a k
+
 b 10k
68%

Subtraction of fractions with different denominators, no LCM.

 a k
-
 b 2k
60%
 a k
-
 b 3k
80%
 a k
-
 b 4k
80%
 a k
-
 b 5k
20%
 a k
-
 b 6k
40%
 a k
-
 b 7k
80%
 a k
-
 b 8k
100%
 a k
-
 b 9k
100%
 a k
-
 b 10k
68%

Addition and subtraction of fractions with different denominators. LCM required.

Hover the pointer over the grid chart to view the tooltip with the facts description.

1234567
 a k
±
 b 2k
 a k
±
 b 3k
 a k
±
 b 4k
 a k
±
 b 5k
 a 2k
±
 b 3k
 a 2k
±
 b 5k
 a 2k
±
 b 7k
 a 3k
±
 b 4k
 a 3k
±
 b 5k

 Perfectly correct answers Need improvement Totally incorrect answers Never practiced