What is 9/20 plus 4/5?
9/20 plus 4/5 equals 5/4 (or 1 1/4 as a mixed number) (or 1.25 in decimal form). Learn the step-by-step solution to add 9/20 and 4/5 using Least Common Denominator and simplification.
Exact Answer
9/20 + 4/5 = 5/4
Simplified Fraction
5/4
Mixed Number
1 1/4
Decimal Value
1.25
Percentage
125%
Step-by-Step Solution: 9/20 + 4/5
Step 1
Find the Least Common Denominator (LCD)
Notice that 20 is an exact multiple of 5 (5 × 4 = 20). The Least Common Denominator (LCD) is simply 20, meaning we only need to scale one fraction.
LCD(20, 5) = 20
Step 2
Convert to Equivalent Fractions with Common Denominator 20
Multiply the numerator and denominator of 9/20 by 1, and multiply the numerator and denominator of 4/5 by 4 so both fractions share the common base 20.
9 × 1/20 × 1 = 9/20 and 4 × 4/5 × 4 = 16/20
Step 3
Add the Numerators
Now add the numerators (9 + 16 = 25) and keep the common denominator 20 unchanged.
9 + 16/20 = 25/20
Step 4
Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 25 and 20, which is 5. Divide both the numerator and denominator by 5.
25 ÷ 5/20 ÷ 5 = 5/4
Step 5
Convert Improper Fraction to a Mixed Number
Since the numerator (5) is greater than the denominator (4), divide 5 by 4: it goes in 1 whole time(s) with a remainder of 1, giving the mixed number 1 1/4.
5/4 = 11/4
Step 6
Decimal & Percentage Representation
Dividing the numerator 5 by denominator 4 yields an exact terminating decimal of 1.25 (or 125%).
5 ÷ 4 = 1.25 (125%)
Visual Representation
The diagram below illustrates 9/20 plus 4/5 visually:
+
=
Summary & Alternative Representations
| Property / Format | Value |
|---|---|
| Lowest Terms Fraction | 5/4 |
| Mixed Number Form | 1 1/4 |
| Decimal Form | 1.25 |
| Percentage | 125% |
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Frequently Asked Questions
What is 9/20 plus 4/5 as a fraction?
9/20 + 4/5 in simplest fraction form is 5/4 (or 1 1/4 as a mixed number).
What is 9/20 plus 4/5 as a decimal?
9/20 + 4/5 converted to a decimal is 1.25.
What is 9/20 plus 4/5 as a percentage?
9/20 + 4/5 expressed as a percentage is 125%.
How do you write 9/20 plus 4/5 as a mixed number?
Because the numerator is greater than the denominator, the improper fraction 5/4 can be written as the mixed number 1 1/4.
Does 9/20 plus 4/5 result in a terminating or repeating decimal?
It results in an exact terminating decimal (1.25) because the denominator in simplest terms contains only prime factors 2 and/or 5.