What is 3/10 plus 2/5? (Answer: 7/10)

Exact Answer

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Problem: What is 3/10 plus 2/5?
Formula / Expression: 3/10 + 2/5
Final Answer: 7/10
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
Notice that 10 is an exact multiple of 5 (5 × 2 = 10). The Least Common Denominator (LCD) is simply 10, meaning we only need to scale one fraction.
Working: LCD(10, 5) = 10

Step 2: Convert to Equivalent Fractions with Common Denominator 10
Multiply the numerator and denominator of 3/10 by 1, and multiply the numerator and denominator of 2/5 by 2 so both fractions share the common base 10.
Working: 3 × 1/10 × 1 = 3/10 and 2 × 2/5 × 2 = 4/10

Step 3: Add the Numerators
Now add the numerators (3 + 4 = 7) and keep the common denominator 10 unchanged.
Working: 3 + 4/10 = 7/10

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 7 and 10 is 1, confirming that 7/10 cannot be reduced further—it is already in its simplest irreducible form.
Working: 7/10

Step 5: Decimal & Percentage Representation
Dividing the numerator 7 by denominator 10 yields an exact terminating decimal of 0.7 (or 70%).
Working: 7 ÷ 10 = 0.7 (70%)

Key Values:
- Simplified Fraction: 7/10
- Mixed Number Form: 7/10
- Decimal Value: 0.7
- Percentage: 70%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-3-10-plus-2-5/
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3/10 + 2/5 = 7/10

Simplified Fraction

7/10

Mixed Number

Proper (7/10)

Decimal Value

0.7

Percentage

70%

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Step-by-Step Solution: 3/10 + 2/5

Step 1

Find the Least Common Denominator (LCD)

Notice that 10 is an exact multiple of 5 (5 × 2 = 10). The Least Common Denominator (LCD) is simply 10, meaning we only need to scale one fraction.

LCD(10, 5) = 10

Step 2

Convert to Equivalent Fractions with Common Denominator 10

Multiply the numerator and denominator of 3/10 by 1, and multiply the numerator and denominator of 2/5 by 2 so both fractions share the common base 10.

3 × 1/10 × 1 = 3/10 and 2 × 2/5 × 2 = 4/10

Step 3

Add the Numerators

Now add the numerators (3 + 4 = 7) and keep the common denominator 10 unchanged.

3 + 4/10 = 7/10

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 7 and 10 is 1, confirming that 7/10 cannot be reduced further—it is already in its simplest irreducible form.

7/10

Step 5

Decimal & Percentage Representation

Dividing the numerator 7 by denominator 10 yields an exact terminating decimal of 0.7 (or 70%).

7 ÷ 10 = 0.7 (70%)

Visual Representation

The diagram below illustrates 3/10 plus 2/5 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`7/10`
Mixed Number Form	`7/10`
Decimal Form	`0.7`
Percentage	`70%`

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Frequently Asked Questions

What is 3/10 plus 2/5 as a fraction?

3/10 + 2/5 in simplest fraction form is 7/10.

What is 3/10 plus 2/5 as a decimal?

3/10 + 2/5 converted to a decimal is 0.7.

What is 3/10 plus 2/5 as a percentage?

3/10 + 2/5 expressed as a percentage is 70%.

Does 3/10 plus 2/5 result in a terminating or repeating decimal?

It results in an exact terminating decimal (0.7) because the denominator in simplest terms contains only prime factors 2 and/or 5.