Decimals Questions: Answers and Explanations

Decimal Questions with Answers presents methods and worked examples to help learners understand decimal numbers and solve problems with confidence. This guide reviews the key concepts of decimals, including place value, comparison, addition, subtraction, multiplication, division, and conversion between fractions and decimals. From basic exercises to application-based questions, each solution focuses on clear steps, logical reasoning, and helpful shortcuts. Worked examples with brief explanations help strengthen understanding and exam preparation.

Table of Contents

• Decimal Questions for Class 4
• Decimal Questions for Class 5
• Decimal Questions for Class 6
• Decimal Questions for Class 7
• Decimal Questions for Class 8
• Advanced Decimal Questions
• Frequently Asked Questions of Decimals Questions

Decimal Questions for Class 4

Q1. What is 4/10 written as a decimal?

(a) 0.04

(b) 0.4

(c) 4.0

(d) 40.0

Solution: 

Answer: (b) 0.4

Since the denominator is 10, the numerator 4 goes in the tenths place, one digit after the decimal point: 4/10 = 0.4.

Q2. Fill in the Blank: 5.6 can be broken down as 5 + ______.

Solution: 

Answer: 0.6

5.6 has a whole number part (5) and a decimal part (0.6, i.e., 6 tenths). So 5.6 = 5 + 0.6.

Q3. Meena bought a pencil for ₹6.50 and an eraser for ₹3.25. How much did she spend in total?

Solution: 

Answer: ₹9.75

Price of Pencil = ₹6.50

Price of Eraser =  ₹3.25

Align the decimal points and add:

  6.50

+ 3.25

------

  9.75

Decimal Questions for Class 5

Q4. Which of these decimals is the greatest: 0.45, 0.4, 0.454, 0.399?

(a) 0.4

(b) 0.45

(c) 0.454

(d) 0.399

Solution:

Answer: (c) 0.454

Compare digit by digit after the decimal point: all four start with 0.3 or 0.4, but 0.454 has the largest hundredths and thousandths digits once tenths are matched (0.400, 0.450, 0.454, 0.399), so 0.454 is the greatest.

Q5. Assertion (A): 3.4 is the same as 3.40.

Reason (R): Adding zeros after the last digit of a decimal number does not change its value.

(a) Both A and R are true, and R correctly explains A.

(b) Both A and R are true, but R does not explain A.

(c) A is true, R is false.

(d) A is false, R is true.

Solution:

Answer: (a)

Both statements are correct, and the reason directly explains why the assertion holds: trailing zeros after the decimal point don't add any value, so 3.4 = 3.40.

Q6. A rope is 15.75 m long. If a piece of 8.5 m is cut off, what length of rope is left?

Solution:

Answer: 7.25 m

Length of rope = 15.75 m

Length of rope cut off = 8.5 m

Length of rope left = 15.75 − 8.50 = 7.25 m.

Decimal Questions for Class 6

Q7. 4.2 × 10 = ?

(a) 0.42

(b) 4.20

(c) 42

(d) 420

Solution:

Answer: (c) 42

Multiplying by 10 shifts the decimal point one place to the right: 4.2 → 42.

Q8. True/False: 0.5 is equal to the fraction 1/2.

Solution:

Answer: True

1/2 = 5/10 = 0.5, so they represent the same value.

Q9. Arrange in ascending order: 6.25, 6.025, 6.205, 6.052

Solution:

Answer: 6.025, 6.052, 6.205, 6.25

Compare place by place after the decimal point (tenths first, then hundredths, then thousandths): 6.025 < 6.052 < 6.205 < 6.25.

Decimal Questions for Class 7

Q10. 2.5 × 1.2 = ?

(a) 2.5

(b) 3.0

(c) 3.5

(d) 30

Solution:

Answer: (b) 3.0

Multiply as whole numbers: 25 × 12 = 300. The total number of decimal places in the factors is 1 + 1 = 2, so place the decimal point two digits from the right: 3.00 = 3.0.

Q11. Assertion (A): 0.04 × 0.02 = 0.0008.

Reason (R): The number of decimal places in the product equals the sum of decimal places in the two factors.

Solution:

Answer: Both A and R are true, and R correctly explains A.

4 × 2 = 8, and the total decimal places = 2 + 2 = 4, so the product needs 4 digits after the decimal point: 0.0008. Both the assertion and the reasoning behind it are correct.

Q12. Rice costs ₹42 per kg. What is the cost of 3.5 kg of rice?

Solution:

Answer: ₹147

Cost of rice = ₹42 per kg

Cost of 3.5 kg rice = 42 × 3.5 = 147.

Decimal Questions for Class 8

Q13. (1.5)² = ?

(a) 2.25

(b) 2.5

(c) 3.0

(d) 22.5

Solution:

Answer: (a) 2.25

1.5 × 1.5 = 2.25 (multiply 15 × 15 = 225, then place the decimal 2 places from the right).

Q14. The recurring decimal 0.6 (0.666...) equals the fraction ______.

Solution:

Answer: 2/3

Let x = 0.666... 

Then 10x = 6.666... 

Subtracting: 10x − x = 6.666... − 0.666... gives 9x = 6, so x = 6/9 = 2/3.

Q15. Find the value of x if 2.5x = 17.5

Solution:

Answer: x = 7

x = 17.5 ÷ 2.5. Multiply both by 10 to clear decimals: 175 ÷ 25 = 7.

Advanced Decimal Questions

Q16. Convert 0.18 (0.181818...) into a fraction.

Solution: 

Step 1: Let x = 0.181818...

Step 2: Since two digits repeat, multiply both sides by 100: 100x = 18.181818...

Step 3: Subtract the original equation: 100x − x = 18.1818... − 0.1818..., which gives 99x = 18.

Step 4: Solve: x = 18/99 = 2/11.

Answer: 0.18 = 2/11

Q17. Simplify: (0.8 × 0.5) + (1.2 ÷ 0.4)

Solution:

Step 1: 0.8 × 0.5 = 0.4

Step 2: 1.2 ÷ 0.4 = 3

Step 3: 0.4 + 3 = 3.4

Answer: 3.4

Q18. A shopkeeper sells 4 notebooks at ₹28.50 each. How much money does he collect in total?

Solution:

Answer: ₹114

Cost of each notebook = ₹28.50

Cost of 4 notebook = 28.50 × 4 = 114.00, i.e., ₹114.

Q19. A container has 5.4 litres of milk. It is poured equally into 6 bottles. How much milk does each bottle get?

Solution:

Answer: 0.9 litres

Total milk in the container = 5.4 litres

Amount of milk each bottle gets = 5.4 ÷ 6 = 0.9 litres per bottle.