What is 19/39 plus 15/21?
19/39 plus 15/21 equals 328/273 (or 1 55/273 as a mixed number) (or 1.201465 in decimal form). Learn the step-by-step solution to add 19/39 and 15/21 using Least Common Denominator and simplification.
Exact Answer
19/39 + 15/21 = 328/273
Simplified Fraction
328/273
Mixed Number
1 55/273
Decimal Value
1.201465
Percentage
120.1465%
Step-by-Step Solution: 19/39 + 15/21
Step 1
Find the Least Common Denominator (LCD)
The denominators 39 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 273 (which is smaller than their product 39 × 21 = 819, keeping the calculation simpler).
LCD(39, 21) = 273
Step 2
Convert to Equivalent Fractions with Common Denominator 273
Multiply the numerator and denominator of 19/39 by 7, and multiply the numerator and denominator of 15/21 by 13 so both fractions share the common base 273.
19 × 7/39 × 7 = 133/273 and 15 × 13/21 × 13 = 195/273
Step 3
Add the Numerators
Now add the numerators (133 + 195 = 328) and keep the common denominator 273 unchanged.
133 + 195/273 = 328/273
Step 4
Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 328 and 273 is 1, confirming that 328/273 cannot be reduced further—it is already in its simplest irreducible form.
328/273
Step 5
Convert Improper Fraction to a Mixed Number
Since the numerator (328) is greater than the denominator (273), divide 328 by 273: it goes in 1 whole time(s) with a remainder of 55, giving the mixed number 1 55/273.
328/273 = 155/273
Step 6
Decimal & Percentage Representation
Dividing the numerator 328 by denominator 273 produces a repeating decimal (approximately 1.201465, or 120.1465%).
328 ÷ 273 = 1.201465 (120.1465%)
Visual Representation
The diagram below illustrates 19/39 plus 15/21 visually:
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Summary & Alternative Representations
| Property / Format | Value |
|---|---|
| Lowest Terms Fraction | 328/273 |
| Mixed Number Form | 1 55/273 |
| Decimal Form | 1.201465 |
| Percentage | 120.1465% |
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Frequently Asked Questions
What is 19/39 plus 15/21 as a fraction?
19/39 + 15/21 in simplest fraction form is 328/273 (or 1 55/273 as a mixed number).
What is 19/39 plus 15/21 as a decimal?
19/39 + 15/21 converted to a decimal is 1.201465.
What is 19/39 plus 15/21 as a percentage?
19/39 + 15/21 expressed as a percentage is 120.1465%.
How do you write 19/39 plus 15/21 as a mixed number?
Because the numerator is greater than the denominator, the improper fraction 328/273 can be written as the mixed number 1 55/273.
Does 19/39 plus 15/21 result in a terminating or repeating decimal?
It results in a repeating decimal (approximately 1.201465...) because the denominator contains prime factors other than 2 and 5.