CBSE Class 7 Mathematics Decimals Assignment Set 03

Q1. Divide 18.324 by 15
Answer: 1.2216
Step-by-step calculation:
\(18.324 \div 15\)
\(= \frac{18.324}{15}\)
\(= 1.2216\)
In simple words: Divide the decimal number 18.324 by 15 using standard long division to get 1.2216.

Exam Tip: Place the decimal point in the quotient directly above the decimal point in the dividend.

Q2. Divide 321.324 by 1.2
Answer: 267.77
Step-by-step calculation:
\(321.324 \div 1.2\)
\(= \frac{321.324}{1.2}\)
Multiply numerator and denominator by 10 to remove the decimal in the divisor:
\(= \frac{3213.24}{12}\)
\(= 267.77\)
In simple words: Shift the decimal point one place to the right in both numbers to make the divisor a whole number, then divide.

Exam Tip: Always make the divisor a whole number by shifting the decimal point equally in both numbers.

Q3. Divide 333.341 by 10, 100, 1000 respectively
Answer: (i) 33.3341, (ii) 3.33341, (iii) 0.333341
Step-by-step calculation:
(i) \(333.341 \div 10 = 33.3341\)
(ii) \(333.341 \div 100 = 3.33341\)
(iii) \(333.341 \div 1000 = 0.333341\)
In simple words: When dividing by powers of 10, shift the decimal point to the left by as many places as there are zeros.

Exam Tip: Counting zeros in 10, 100, and 1000 tells you exactly how many places to move the decimal point to the left.

Q4. Divide 834.34 by 3.7
Answer: 225.49729
Step-by-step calculation:
\(834.34 \div 3.7\)
\(= \frac{834.34}{3.7}\)
Multiply numerator and denominator by 10:
\(= \frac{8343.4}{37}\)
\(= 225.49729\)
In simple words: Convert the divisor into a whole number by shifting the decimal point, then perform division.

Exam Tip: Maintain precision by calculating up to at least 5 decimal places if necessary.

Q5. Divide 32.4256 by 0.24
Answer: 135.10666
Step-by-step calculation:
\(32.4256 \div 0.24\)
\(= \frac{32.4256}{0.24}\)
Multiply numerator and denominator by 100:
\(= \frac{3242.56}{24}\)
\(= 135.10666\)
In simple words: Shift the decimal point two places to the right for both numbers and divide.

Q6. Divide 0.08892 by 0.36
Answer: 0.247
Step-by-step calculation:
\(0.08892 \div 0.36\)
\(= \frac{0.08892}{0.36}\)
Multiply numerator and denominator by 100:
\(= \frac{8.892}{36}\)
\(= 0.247\)
In simple words: Make the divisor a whole number by moving the decimal two places right, then divide the resulting decimal.

Exam Tip: Ensure zeros are placed correctly in the quotient when the dividend becomes smaller than the divisor.

Q7. Divide 2.13456 by 1.25
Answer: 1.707648
Step-by-step calculation:
\(2.13456 \div 1.25\)
\(= \frac{2.13456}{1.25}\)
Multiply numerator and denominator by 100:
\(= \frac{213.456}{125}\)
\(= 1.707648\)
In simple words: Multiply both numbers by 100 to eliminate the decimal in 1.25, then divide.

Exam Tip: Division by 125 can also be performed by multiplying the numerator by 8 and dividing by 1000.

Q8. Divide 374.567 by 8.92
Answer: 41.991816
Step-by-step calculation:
\(374.567 \div 8.92\)
\(= \frac{374.567}{8.92}\)
Multiply numerator and denominator by 100:
\(= \frac{37456.7}{892}\)
\(= 41.991816\)
In simple words: Shift the decimal point two places to the right in both numbers to simplify the divisor.

Exam Tip: Double check multiplication steps when verifying decimal divisions.

Q9. Divide 333.33 by 0.0313
Answer: 10649.52
Step-by-step calculation:
\(333.33 \div 0.0313\)
\(= \frac{333.33}{0.0313}\)
Multiply numerator and denominator by 10000:
\(= \frac{3333300}{313}\)
\(= 10649.52\)
In simple words: Move the decimal four places to the right for both numbers to remove decimals from the divisor.

Exam Tip: Add trailing zeros to the dividend if it has fewer decimal places than the divisor.

Q10. Divide 456.007 by 1.273
Answer: 358.21445
Step-by-step calculation:
\(456.007 \div 1.273\)
\(= \frac{456.007}{1.273}\)
Multiply numerator and denominator by 1000:
\(= \frac{456007}{1273}\)
\(= 358.21445\)
In simple words: Since both numbers have three decimal places, multiply both by 1000 and divide whole numbers.

Exam Tip: Equalizing decimal places before division helps avoid calculation errors.