What is 1/4 + 1/5?

Calculate 1/4 + 1/5 with a complete step-by-step solution. Learn how to add fractions and understand the process.

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Answer: 1/4 + 1/5 = \frac{9}{20}
Step-by-Step Solution
Step 1 Identify the Fractions

We need to add two fractions: 1/4 and 1/5

To add fractions, they must have the same denominator (bottom number).

\frac{1}{4} + \frac{1}{5} = ?
Step 2 Find the Least Common Denominator (LCD)

The denominators are different (4 and 5), so we need to find a common denominator.

The LCD is the smallest number that both 4 and 5 divide into evenly.

LCD = 4 × 5 = 20

\text{LCD}(4, 5) = 20
Step 3 Convert First Fraction

Multiply 1/4 to get denominator of 20:

Multiply both top and bottom by 5

\frac{1}{4} = \frac{1 \times 5}{4 \times 5} = \frac{5}{20}
Step 4 Convert Second Fraction

Multiply 1/5 to get denominator of 20:

Multiply both top and bottom by 4

\frac{1}{5} = \frac{1 \times 4}{5 \times 4} = \frac{4}{20}
Step 5 Add the Fractions

Now both fractions have the same denominator (20).

Add the numerators: 5 + 4 = 9

\frac{5}{20} + \frac{4}{20} = \frac{5 + 4}{20} = \frac{9}{20}