What is 9/21 plus 12/21?
9/21 plus 12/21 equals 1 (or 1 in decimal form). Learn the step-by-step solution to add 9/21 and 12/21 using Least Common Denominator and simplification.
Exact Answer
9/21 + 12/21 = 1
Simplified Fraction
1
Mixed Number
1
Decimal Value
1
Percentage
100%
Step-by-Step Solution: 9/21 + 12/21
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.
9/21 + 12/21
Step 2
Add the Numerators
Now add the numerators (9 + 12 = 21) and keep the common denominator 21 unchanged.
9 + 12/21 = 21/21
Step 3
Simplify to an Exact Whole Number
Notice that the numerator (21) is completely divisible by the denominator (21). Dividing 21 by 21 yields the whole number 1 with zero remainder.
21/21 = 1
Step 4
Decimal & Percentage Representation
Dividing the numerator 1 by denominator 1 yields an exact terminating decimal of 1 (or 100%).
1 ÷ 1 = 1 (100%)
Visual Representation
The diagram below illustrates 9/21 plus 12/21 visually:
+
=
Summary & Alternative Representations
| Property / Format | Value |
|---|---|
| Lowest Terms Fraction | 1 |
| Mixed Number Form | 1 |
| Decimal Form | 1 |
| Percentage | 100% |
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Frequently Asked Questions
What is 9/21 plus 12/21 as a fraction?
9/21 + 12/21 in simplest fraction form is 1.
What is 9/21 plus 12/21 as a decimal?
9/21 + 12/21 converted to a decimal is 1.
What is 9/21 plus 12/21 as a percentage?
9/21 + 12/21 expressed as a percentage is 100%.
Is the answer to 9/21 plus 12/21 a whole number?
Yes, 9/21 + 12/21 simplifies completely to the whole number 1 with no remaining fractional part.