Quantitative Aptitude · Numbers & Simplification
Decimal Fractions — Questions & Answers
Decimal fraction questions ask you to convert between fractions and decimals, compare and order decimals, and compute with them quickly. Recurring decimals convert to fractions with a standard trick.
- 5 solved questions
- Step-by-step AI walkthroughs
- Key formulas included
Key formulas
To divide by a decimal, shift the point in both numbers: 0.040.36=436=9
Pure recurring: 0.ab=99ab; e.g. 0.27=9927=113
Mixed recurring: 0.ab=90ab−a
5 solved Decimal Fractions questions
Express 0.25 as a fraction in its lowest terms.
Solution — answer A
0.25=10025, and dividing numerator and denominator by 25 gives 41.
5 steps · reveal one at a timeStep 1: Understand the decimal
The number 0.25 has two decimal places. The last digit, 5, is in the hundredths place. This means 0.25 can be read as "twenty-five hundredths".
Step 2: Convert to fraction
To convert 0.25 to a fraction, we can write the number after the decimal point as the numerator and use 100 as the denominator. So, 0.25=10025.
Step 3: Simplify the fraction
Now we need to simplify the fraction 10025 to its lowest terms. Find the greatest common divisor (GCD) of 25 and 100. Both numbers are divisible by 25.
Step 4: Divide by GCD
Divide both the numerator and the denominator by 25: 100÷2525÷25=41. This fraction is now in its lowest terms as 1 and 4 share no common factors other than 1.
Step 5: The answer
So the answer is (A) 41. The decimal 0.25 is equivalent to the fraction 41 when expressed in its simplest form.
Evaluate 0.0080.48.
Solution — answer C
Multiply top and bottom by 1000: 0.0080.48=8480=60.
5 steps · reveal one at a timeStep 1: Understand the problem
We need to evaluate the expression 0.0080.48. Dividing decimals can be challenging, so our first goal is to convert this into a division of whole numbers.
Step 2: Remove decimals
To eliminate the decimals, we multiply both the numerator and the denominator by the same power of 10. This keeps the value of the fraction unchanged.
Step 3: Find the multiplier
Look at the denominator, 0.008. It has three decimal places. To make it a whole number, we need to multiply it by 1000. We must also multiply the numerator by 1000.
Step 4: Simplify the fraction
Multiplying both parts by 1000 gives us: 0.008×10000.48×1000=8480. This is a much simpler division.
Step 5: The answer
Now, perform the division: 480÷8=60. So the answer is (C) 60, which is the result of the simplified division.
Which of these is the largest number: 0.7, 0.71, 0.0709, 0.717?
Solution — answer D
Compare digit by digit after the point. 0.717 has 7 tenths, 1 hundredth and 7 thousandths, which exceeds 0.710 and 0.700; 0.0709 has only 0 tenths.
5 steps · reveal one at a timeStep 1: Align Decimals
To compare decimal numbers, it's helpful to align them and add trailing zeros so they all have the same number of decimal places. This makes comparison easier. We can write the numbers as: 0.7000, 0.7100, 0.0709, 0.7170.
Step 2: Compare Tenths Digit
Now, let's compare the first digit after the decimal point (the tenths place). We have 0.7, 0.7, 0.0, and 0.7. The number 0.0709 has a 0 in the tenths place, making it smaller than the others, which all have 7.
Step 3: Compare Hundredths Digit
Next, compare the numbers that have 7 in the tenths place: 0.7000, 0.7100, and 0.7170. Look at the hundredths digit. We have 0, 1, and 1. The number 0.7000 has 0 in the hundredths place, making it smaller than 0.7100 and 0.7170.
Step 4: Compare Thousandths Digit
Finally, we compare 0.7100 and 0.7170. Both have 7 in the tenths place and 1 in the hundredths place. Now look at the thousandths digit. 0.7100 has 0, while 0.7170 has 7. Since 7 is greater than 0, 0.7170 is the largest number.
Step 5: The answer
So the answer is (D) 0.717. This number has 7 tenths, 1 hundredth, and 7 thousandths, which is greater than all other options when compared digit by digit.
Find the value of 0.6+0.7+0.8.
Solution — answer A
Each single-digit recurring decimal is that digit over 9: 96+97+98=921=37=2.3.
5 steps · reveal one at a timeStep 1: Convert to fractions
Remember that a single-digit recurring decimal, like 0.d, can be written as the fraction d/9. We will apply this rule to each term in the sum to convert them into fractions.
Step 2: Rewrite the sum
Using the conversion rule, we can rewrite the expression as a sum of fractions: 0.6+0.7+0.8=6/9+7/9+8/9. Now, we can add these fractions.
Step 3: Add the fractions
Since all fractions have the same denominator, we simply add their numerators: (6+7+8)/9=21/9. This gives us a single fraction representing the sum.
Step 4: Simplify and convert
The fraction 21/9 can be simplified by dividing both numerator and denominator by 3, resulting in 7/3. Converting 7/3 back to a decimal gives 2.3.
Step 5: The answer
So the answer is (A) 2.3, because the sum of the recurring decimals simplifies to 7/3, which is 2.3.
If 0.144144=x14.4, find x.
Solution — answer B
0.144144=1000, so x14.4=1000, which gives x=100014.4=0.0144.
5 steps · reveal one at a timeStep 1: Simplify the fraction
First, let's simplify the left side of the equation, 0.144144. Notice that 144 is 1000 times 0.144. Therefore, 0.144144=1000.
Step 2: Form the equation
Now that we know the left side equals 1000, we can substitute this back into the original equation. This gives us the simpler equation: 1000=x14.4.
Step 3: Isolate x
To find x, we need to isolate it. We can rearrange the equation by multiplying both sides by x, which gives 1000x=14.4. Then, divide both sides by 1000 to solve for x.
Step 4: Calculate x
Dividing 14.4 by 1000 means moving the decimal point three places to the left. So, x=100014.4=0.0144. This is our final value for x.
Step 5: The answer
So the answer is (B) 0.0144. This value correctly satisfies the original equation.
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