What is 1/7 plus 3/7?
What is 1/7 plus 3/7?
Answer
As a decimal: ≈ 0.5714
4/7 is the result of adding 1/7 and 3/7.
Steps to add 1/7 and 3/7
Only parts of the same size can be counted together, so 1/7 + 3/7 is solved by giving both fractions the same denominator and then adding the numerators. Here is every step.
Step 1: Check the denominators
Both fractions already have the denominator 7, so there is nothing to rewrite.
Step 2: Add the numerators
The denominator stays as it is — it says how big each part is, and that has not changed. Only the count of parts is added up.
1/7 + 3/7
=(1 + 3)/7
=4/7
Answer
1/7 + 3/7
=4/7
As a decimal, 1/7 + 3/7 ≈ 0.5714 — the decimal form is rounded, the fraction 4/7 is the exact answer.
Related Calculations
See Also
- Fraction to Decimal Converter - Convert Fraction to Decimal
- Fraction Comparison Calculator - Compare two fractions and find out which is larger
- Dividing Fractions Calculator - Divide fractions, mixed numbers and whole numbers step by step
- Fraction to Mixed Number Converter - Convert an Improper Fraction to a Mixed Number
- Multiplying Fractions Calculator - Multiply fractions, mixed numbers and whole numbers step by step
- Fraction Simplifier Calculator - Simplify Fraction to its Lowest Terms
- Subtracting Fractions Calculator - Subtract fractions, mixed numbers and whole numbers step by step
- Percent to Fraction Converter - Convert Percents to Fractions

Fraction Addition Table
| Addition | Result | Decimal Form |
|---|---|---|
| 1/7 + 1/5 | 12/35 | ≈ 0.3429 |
| 1/7 + 2/9 | 23/63 | ≈ 0.3651 |
| 1/7 + 1/4 | 11/28 | ≈ 0.3929 |
| 1/7 + 2/8 | 11/28 | ≈ 0.3929 |
| 1/7 + 2/7 | 3/7 | ≈ 0.4286 |
| 1/7 + 3/10 | 31/70 | ≈ 0.4429 |
| 1/7 + 1/3 | 10/21 | ≈ 0.4762 |
| 1/7 + 3/8 | 29/56 | ≈ 0.5179 |
| 1/7 + 2/5 | 19/35 | ≈ 0.5429 |
| 1/7 + 5/12 | 47/84 | ≈ 0.5595 |
| 1/7 + 3/7 | 4/7 | ≈ 0.5714 |
| 1/7 + 1/2 | 9/14 | ≈ 0.6429 |
| 1/7 + 2/4 | 9/14 | ≈ 0.6429 |
| 1/7 + 3/5 | 26/35 | ≈ 0.7429 |
| 1/7 + 5/8 | 43/56 | ≈ 0.7679 |
| 1/7 + 2/3 | 17/21 | ≈ 0.8095 |
| 1/7 + 7/10 | 59/70 | ≈ 0.8429 |
| 1/7 + 5/7 | 6/7 | ≈ 0.8571 |
| 1/7 + 3/4 | 25/28 | ≈ 0.8929 |
| 1/7 + 4/5 | 33/35 | ≈ 0.9429 |
Adding Fractions Calculator
This calculator adds two fractions and shows the whole solution, not just the answer. Mixed numbers and whole numbers are accepted on both sides, so you can add 2 1/3 to 1 just as easily as 1/2 to 1/3.
For example, it can help you find out what is 1/7 plus 3/7? (The answer is: 4/7).
Enter the first fraction on the left and the second one on the right (for example '1/7' and '3/7'), then press the button.
The result is given as a fraction in its lowest terms, as a mixed number when it is greater than one, and as a decimal — with an approximation sign whenever the decimal never ends.
Every page also shows why the method works: only parts of the same size can be counted together, so both fractions are first rewritten over their least common denominator and only then are the numerators added.