MathematicsClass 7Another Peek

Another Peek | Class 7 Mathematics Notes

By ConceptScroll Team · Published on 17 July 2026 · 3 min read

Another Peek – this guide gives you a concise, exam-ready overview of Another Peek from Class 7 Mathematics, written by ConceptScroll editors and reviewed against the latest NCERT textbook.

4.2 Decimal Multiplication

Decimal multiplication involves multiplying numbers that have digits after the decimal point. The process is an extension of multiplication of whole numbers and fractions. The key idea is to first ignore the decimal points and multiply the numbers as whole numbers, then place the decimal point in the product based on the total number of decimal places in the factors. For example, multiplying 9.5 by 5 can be done by converting 9.5 to the fraction 95/10 and 5 to 5/1, multiplying numerators and denominators to get 475/10 = 47.5. Another example is multiplying 12.5 km per litre by 7.5 litres to find distance covered: (125/10) × (75/10) = 9375/100 = 93.75 km. The chapter explains that the product of two decimals can be greater than, less than, or between the numbers multiplied depending on their values relative to 1. For instance, 0.25 × 0.8 = 0.2 is less than both numbers, while 2.25 × 8 = 18 is greater than both. The number of decimal places in the product equals the sum of decimal places in the multiplicand and multiplier. This is illustrated through examples such as 5.7 × 13.35 = 75.81. A general rule is framed: multiply the numbers ignoring decimals, then place the decimal point in the product so that the number of decimal digits equals the sum of decimal digits in the numbers multiplied. This section also includes real-world problems like calculating the area of a rectangle with decimal sides and distance walked by Ajay in a week, reinforcing practical applications of decimal multiplication.

📊 Diagram: Diagrams showing multiplication of decimals with place value expansions and examples of decimal multiplication applied to real-life scenarios like buying pens and calculating distances.

🧪 Activity: Students are encouraged to find products of decimals and natural numbers, and observe when products are natural numbers or decimals.

🔗 Connection: This section prepares students to understand decimal division by reinforcing the concept of decimal place values and operations with decimals.

Frequently asked questions

1. A 210 gram packet of peanut chikki costs ₹70.5, while a 110 gram packet of potato chips costs ₹33.25. Which is cheaper?

To find which is cheaper, calculate the cost per gram for each.

Cost per gram of peanut chikki = ₹70.5 / 210 g = ₹0.3357 per gram Cost per gram of potato chips = ₹33.25 / 110 g = ₹0.3023 per gram

Since ₹0.3023 < ₹0.3357, the potato chips are cheaper.

2. Write the decimal number at the arrow mark:

The decimal number at the arrow mark is 0.7.

3. Shyamala bought 3 kg bananas at ₹30/- per kg. She counted 35 bananas in all. She sells each banana for ₹5/-. How much profit does she make selling all the bananas?

Cost price of 3 kg bananas = 3 × ₹30 = ₹90 Number of bananas = 35 Selling price per banana = ₹5 Total selling price = 35 × ₹5 = ₹175 Profit = Selling price - Cost price = ₹175 - ₹90 = ₹85

Shyamala makes a profit of ₹85.

4. A teacher placed textbooks that are 2.5 cm thick on a bookshelf. The teacher wanted to place 80 textbooks on the shelf. The bookshelf is 160 cm long. How many books could be placed on the shelf? Was there any space left? If yes, how much?

Thickness of one textbook = 2.5 cm Number of textbooks teacher wants to place = 80 Total thickness needed = 80 × 2.5 = 200 cm Bookshelf length = 160 cm

Since 200 cm > 160 cm, all 80 books cannot be placed. Number of books that can be placed = 160 cm ÷ 2.5 cm = 64 books

Space left after placing 64 books = 160 cm - (64 × 2.5 cm) = 160 - 160 = 0 cm

So, 64 books can be placed and no space is left.