CBSE Class 5 Mathematics Revision Worksheet Set 21

1. Multiply the following fractions:

Question 1(1). \(\frac{8}{28} \times \frac{3}{7} =\)
Answer: \(\frac{8}{28} \times \frac{3}{7} = \frac{2}{7} \times \frac{3}{7} = \frac{6}{49}\)
In simple words: Simplify the first fraction by dividing numerator and denominator by 4, then multiply the numerators straight across and the denominators straight across.

Exam Tip: Always simplify fractions before multiplying to make your calculations easier.

Question 1(2). \(\frac{2}{7} \times \frac{6}{7} =\)
Answer: \(\frac{2}{7} \times \frac{6}{7} = \frac{2 \times 6}{7 \times 7} = \frac{12}{49}\)
In simple words: Multiply the numerators together and the denominators together since no common factors can be simplified.

Exam Tip: Check if the numerators and denominators share any common factors before finalizing the product.

Question 1(3). \(\frac{9}{14} \times \frac{6}{7} =\)
Answer: \(\frac{9}{14} \times \frac{6}{7} = \frac{9 \times 3}{7 \times 7} = \frac{27}{49}\)
In simple words: Cancel out the common factor 2 from 6 and 14, then multiply the remaining numbers.

Exam Tip: Cross-canceling common factors between any numerator and denominator saves time.

Question 1(4). \(\frac{8}{20} \times \frac{1}{20} =\)
Answer: \(\frac{8}{20} \times \frac{1}{20} = \frac{2}{5} \times \frac{1}{20} = \frac{2}{100} = \frac{1}{50}\)
In simple words: Reduce \(\frac{8}{20}\) to \(\frac{2}{5}\), then multiply straight across to get \(\frac{2}{100}\), and simplify to \(\frac{1}{50}\).

Exam Tip: Always reduce the final fraction to its lowest terms.

Question 1(5). \(\frac{6}{7} \times \frac{7}{14} =\)
Answer: \(\frac{6}{7} \times \frac{7}{14} = \frac{6}{7} \times \frac{1}{2} = \frac{6}{14} = \frac{3}{7}\)
In simple words: Cancel the 7s diagonally, then multiply \(\frac{6}{1} \times \frac{1}{2}\) to get \(\frac{6}{2} = 3\), or simplify \(\frac{6}{14}\) to \(\frac{3}{7}\).

Exam Tip: Diagonal canceling is very effective when identical numbers appear in a numerator and a denominator.

Question 1(6). \(\frac{4}{6} \times \frac{2}{6} =\)
Answer: \(\frac{4}{6} \times \frac{2}{6} = \frac{2}{3} \times \frac{1}{3} = \frac{2}{9}\)
In simple words: Reduce both fractions first to \(\frac{2}{3}\) and \(\frac{1}{3}\), then multiply numerators and denominators.

Exam Tip: Simplifying fractions before multiplication prevents working with large numbers.

3. Add the following fractions:

Question 3(1). \(\frac{1}{5} + \frac{1}{10} =\)
Answer:
Find the least common multiple (LCM) of 5 and 10, which is 10.
Convert \(\frac{1}{5}\) to \(\frac{2}{10}\).
\(\frac{2}{10} + \frac{1}{10} = \frac{3}{10}\)
In simple words: Make the denominators the same by finding a common multiple, then add the numerators.

Exam Tip: Never add denominators directly when adding fractions.

Question 3(2). \(\frac{2}{6} + \frac{2}{8} =\)
Answer:
Simplify fractions first: \(\frac{2}{6} = \frac{1}{3}\) and \(\frac{2}{8} = \frac{1}{4}\).
Find the LCM of 3 and 4, which is 12.
\(\frac{1}{3} = \frac{4}{12}\) and \(\frac{1}{4} = \frac{3}{12}\)
\(\frac{4}{12} + \frac{3}{12} = \frac{7}{12}\)
In simple words: Simplify the fractions first to make finding a common denominator easier.

Question 3(3). \(\frac{2}{8} + \frac{3}{8} =\)
Answer:
Since denominators are already equal, add the numerators directly:
\(\frac{2 + 3}{8} = \frac{5}{8}\)
In simple words: When denominators are the same, just add the top numbers and keep the bottom number the same.

Exam Tip: Always check if denominators match before adding.

Question 3(4). \(\frac{2}{3} + \frac{2}{5} =\)
Answer:
Find the LCM of 3 and 5, which is 15.
\(\frac{2}{3} = \frac{10}{15}\)
\(\frac{2}{5} = \frac{6}{15}\)
\(\frac{10}{15} + \frac{6}{15} = \frac{16}{15} = 1\frac{1}{15}\)
In simple words: Convert both fractions to have a denominator of 15 and add the numerators.

Exam Tip: Improper fractions can be converted into mixed numbers as a final step.

4. Find the difference:

Question 4(1). \(\frac{3}{5} - \frac{1}{5} =\)
Answer:
\(\frac{3 - 1}{5} = \frac{2}{5}\)
In simple words: Subtract the numerators while keeping the common denominator the same.

Exam Tip: Denominators must be identical before performing subtraction.

Question 4(2). \(\frac{5}{7} - \frac{2}{7} =\)
Answer:
\(\frac{5 - 2}{7} = \frac{3}{7}\)
In simple words: Subtract 2 from 5 in the numerator and keep 7 as the denominator.

Exam Tip: Double-check subtraction results in the numerator.

Question 4(3). \(\frac{7}{15} - \frac{1}{5} =\)
Answer:
Find the LCM of 15 and 5, which is 15.
Convert \(\frac{1}{5}\) to \(\frac{3}{15}\).
\(\frac{7}{15} - \frac{3}{15} = \frac{4}{15}\)
In simple words: Make denominators equal to 15 before subtracting the numerators.

Exam Tip: Use the larger denominator if it is a multiple of the smaller denominator.

Question 4(4). \(\frac{5}{6} - \frac{2}{6} =\)
Answer:
\(\frac{5 - 2}{6} = \frac{3}{6} = \frac{1}{2}\)
In simple words: Subtract numerators to get \(\frac{3}{6}\) and simplify to \(\frac{1}{2}\).

Exam Tip: Always reduce your final answer to its simplest form.

Comparing and ordering decimals

Compare the decimals. Which decimal is greater?

Question 1. 7.9 and 8.1
Answer: 8.1
Comparing whole number parts: 8 > 7, so 8.1 > 7.9.
In simple words: Compare the numbers before the decimal point first. Since 8 is greater than 7, 8.1 is greater.

Exam Tip: Whole numbers take priority over decimal digits when comparing.

Question 2. 0.5 and 0.62
Answer: 0.62
Align decimal places: 0.50 and 0.62. Comparing tenths place: 6 > 5, so 0.62 > 0.5.
In simple words: Add a zero to 0.5 to make it 0.50, then compare it with 0.62.

Question 3. 3.6 and 0.94
Answer: 3.6
Comparing whole number parts: 3 > 0, so 3.6 > 0.94.
In simple words: The whole number 3 is greater than 0, making 3.6 the larger number instantly.

Exam Tip: Always look at the whole number part first before checking decimal places.

Question 4. 0.4 and 0.67
Answer: 0.67
Align decimal places: 0.40 and 0.67. Comparing tenths place: 6 > 4, so 0.67 > 0.4.
In simple words: 0.4 can be written as 0.40, which is smaller than 0.67.

Exam Tip: Do not be fooled by more digits; compare place value by place value from left to right.

Question 5. 1.6 and 1.9
Answer: 1.9
Whole numbers are equal (1 = 1). Comparing tenths place: 9 > 6, so 1.9 > 1.6.
In simple words: Since the whole numbers are the same, compare the tenths digit. 9 is greater than 6.

Question 6. 0.31 and 3.10
Answer: 3.10
Comparing whole number parts: 3 > 0, so 3.10 > 0.31.
In simple words: 3.10 has a whole number of 3, whereas 0.31 has 0.

Exam Tip: Check the whole number part first.

Question 7. 8.5 and 6.9
Answer: 8.5
Comparing whole number parts: 8 > 6, so 8.5 > 6.9.
In simple words: 8 is greater than 6, so 8.5 is larger.

Exam Tip: The larger whole number determines the larger decimal.

Question 8. 6.75 and 6.71
Answer: 6.75
Whole numbers are equal (6 = 6). Tenths are equal (7 = 7). Comparing hundredths place: 5 > 1, so 6.75 > 6.71.
In simple words: Compare digit by digit. 5 hundredths is greater than 1 hundredth.

Exam Tip: Compare corresponding place values from left to right until you find a difference.

Find the greatest decimal.

Question 1. 2.9 and 2.75 and 2.6
Answer: 2.9
Align decimal places: 2.90, 2.75, 2.60. Comparing tenths: 9 is the largest tenths digit.
In simple words: 2.9 is equivalent to 2.90, which is larger than 2.75 and 2.60.

Exam Tip: Equalize decimal lengths by adding zeros before comparing.

Question 2. 0.97 and 1.09 and 1.3
Answer: 1.3
Whole numbers are 0, 1, and 1. Comparing decimals with whole number 1: 1.09 and 1.30. Since 3 > 0, 1.3 is the greatest.
In simple words: 1.3 is equal to 1.30, which is greater than 1.09 and 0.97.

Exam Tip: Look at the whole numbers first to eliminate smaller values immediately.

Question 3. 4.9 and 3.87 and 4.75
Answer: 4.9
Comparing numbers with whole number 4: 4.90 and 4.75. Since 9 > 7, 4.9 is the greatest.
In simple words: Compare 4.90 and 4.75; 4.90 is larger than 3.87 and 4.75.

Exam Tip: Fill missing decimal places with zeros to avoid mistakes.

Write the decimals in order from greatest to least.

Question 1. 0.33, 3.1, 0.3
Answer: 3.1, 0.33, 0.3
Align decimals: 0.33, 3.10, 0.30. Ordering from greatest to least gives 3.1, 0.33, 0.3.
In simple words: 3.1 is the largest because of its whole number 3. Between 0.33 and 0.30, 0.33 is greater.

Exam Tip: Pad with zeros to ensure all numbers have the same number of decimal digits before ordering.

Question 2. 24.95, 23.9, 24.5
Answer: 24.95, 24.5, 23.9
Align decimals: 24.95, 23.90, 24.50. Comparing 24-series: 24.95 > 24.50. 23.90 is the smallest.
In simple words: Compare whole numbers first, then compare tenths and hundredths.

Exam Tip: Group numbers by their whole number part first.

Question 3. 7.5, 6.95, 7.58
Answer: 7.58, 7.5, 6.95
Align decimals: 7.50, 6.95, 7.58. Comparing 7-series: 7.58 > 7.50. 6.95 is the smallest.
In simple words: 7.58 is greater than 7.50, and both are greater than 6.95.

Exam Tip: Make decimal lengths equal to prevent ordering errors.

Find the answer to each problem.

Question 1. The Weather Bureau reported 5.18 inches of rain in March, 6.74 inches in April, and 5.23 inches in May. Which month had the least rainfall?
Answer: March
Comparing rainfall values: 5.18, 6.74, and 5.23.
Comparing whole numbers: 5 is less than 6.
Comparing 5-series decimals: 5.18 and 5.23. Since 1 < 2, 5.18 is the smallest.
Therefore, March had the least rainfall.
In simple words: Compare 5.18, 6.74, and 5.23 to find the smallest number, which is 5.18 for March.

Exam Tip: Identify whether the question asks for the greatest or least value before concluding.

Question 2. A postal worker walked 4.5 miles on Wednesday, 3.75 miles on Thursday, and 4.25 miles on Friday. Which day did she walk the farthest?
Answer: Wednesday
Comparing distances: 4.50, 3.75, and 4.25.
Comparing whole numbers: 4 > 3, so Thursday is eliminated.
Comparing 4-series decimals: 4.50 and 4.25. Since 5 > 2, 4.50 is the greatest.
Therefore, she walked the farthest on Wednesday.
In simple words: Find the largest decimal among 4.50, 3.75, and 4.25, which is 4.50 (Wednesday).

Exam Tip: Add a trailing zero to 4.5 to make it 4.50 so it matches the two-digit decimal format of the other numbers.