What is 8/21 plus 10/21?
8/21 plus 10/21 equals 6/7 (or 0.857143 in decimal form). Learn the step-by-step solution to add 8/21 and 10/21 using Least Common Denominator and simplification.
Exact Answer
8/21 + 10/21 = 6/7
Simplified Fraction
6/7
Mixed Number
Proper (6/7)
Decimal Value
0.857143
Percentage
85.7143%
Step-by-Step Solution: 8/21 + 10/21
Step 1
Check the Denominators (Like Fractions)
Both fractions already share the identical denominator (21). Because these are like fractions, no conversion to a common denominator is required—we directly add their numerators while keeping the denominator 21.
8/21 + 10/21
Step 2
Add the Numerators
Now add the numerators (8 + 10 = 18) and keep the common denominator 21 unchanged.
8 + 10/21 = 18/21
Step 3
Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 18 and 21, which is 3. Divide both the numerator and denominator by 3.
18 ÷ 3/21 ÷ 3 = 6/7
Step 4
Decimal & Percentage Representation
Dividing the numerator 6 by denominator 7 produces a repeating decimal (approximately 0.857143, or 85.7143%).
6 ÷ 7 = 0.857143 (85.7143%)
Visual Representation
The diagram below illustrates 8/21 plus 10/21 visually:
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Summary & Alternative Representations
| Property / Format | Value |
|---|---|
| Lowest Terms Fraction | 6/7 |
| Mixed Number Form | 6/7 |
| Decimal Form | 0.857143 |
| Percentage | 85.7143% |
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Frequently Asked Questions
What is 8/21 plus 10/21 as a fraction?
8/21 + 10/21 in simplest fraction form is 6/7.
What is 8/21 plus 10/21 as a decimal?
8/21 + 10/21 converted to a decimal is 0.857143.
What is 8/21 plus 10/21 as a percentage?
8/21 + 10/21 expressed as a percentage is 85.7143%.
Does 8/21 plus 10/21 result in a terminating or repeating decimal?
It results in a repeating decimal (approximately 0.857143...) because the denominator contains prime factors other than 2 and 5.