CBSE Class 4 Maths Revision Worksheet Set 25

Question 1. Find the product by lattice multiplication.
a) \(38 \times 29\)
b) \(95 \times 18\)
Answer: For part (a) \(38 \times 29\):
- Set up a 2x2 grid with 3 and 8 across the top, and 2 and 9 down the right side.
- Multiply each digit: \(3 \times 2 = 06\), \(8 \times 2 = 16\), \(3 \times 9 = 27\), \(8 \times 9 = 72\).
- Add along the diagonals from right to left:
- Ones diagonal: 2
- Tens diagonal: \(6 + 7 + 2 = 15\) (write 5, carry 1)
- Hundreds diagonal: \(1 + 6 + 1 + 2 = 10\) (write 0, carry 1)
- Thousands diagonal: \(1 + 0 = 1\)
- Product = 1102

For part (b) \(95 \times 18\):
- Set up a 2x2 grid with 9 and 5 across the top, and 1 and 8 down the right side.
- Multiply each digit: \(9 \times 1 = 09\), \(5 \times 1 = 05\), \(9 \times 8 = 72\), \(5 \times 8 = 40\).
- Add along the diagonals from right to left:
- Ones diagonal: 0
- Tens diagonal: \(5 + 4 + 2 = 11\) (write 1, carry 1)
- Hundreds diagonal: \(1 + 0 + 7 + 9 = 17\) (write 7, carry 1)
- Thousands diagonal: \(1 + 0 = 1\)
- Product = 1710
In simple words: Lattice multiplication uses a grid to break down multiplication into easier single-digit steps before adding them diagonally.

Exam Tip: Always align your diagonals properly and write the carries clearly to avoid addition errors in lattice grids.

Question 2. Complete the table.
Answer:
- Formula for Profit: Selling Price - Cost Price (when Selling Price > Cost Price)
- Formula for Loss: Cost Price - Selling Price (when Cost Price > Selling Price)

In simple words: If you sell an item for more than you bought it, you make a profit. If you sell it for less, you incur a loss.

Exam Tip: Always subtract the smaller amount from the larger amount when finding the difference for profit or loss.

Question 3. A fruit seller bought mangoes for 65 rupees per kg and sold it for 69 rupees per kg. How much did he earn by selling 50kg of mangoes?
Answer:
Cost price of 1 kg of mangoes = Rs. 65
Selling price of 1 kg of mangoes = Rs. 69
Profit on 1 kg of mangoes = Rs. 69 - Rs. 65 = Rs. 4
Total quantity sold = 50 kg
Total earning (profit) = \(50 \times 4 =\) Rs. 200
In simple words: Find the profit on 1 kg by subtracting the buying price from the selling price, then multiply by the total kilograms sold.

Exam Tip: You can also find the total selling price (\(50 \times 69 = 3450\)) and total cost price (\(50 \times 65 = 3250\)), then subtract them (\(3450 - 3250 = 200\)) to get the same result.

Question 4. A person earns Rs. 900 in a day. What is his yearly income?
Answer:
Daily income = Rs. 900
Number of days in a year = 365 days
Yearly income = \(365 \times 900\)
\(365 \times 9 = 3285\)
\(3285 \times 100 = 328500\)
Yearly income = Rs. 3,28,500
In simple words: Multiply one day's earnings by the total number of days in a standard year (365 days).

Exam Tip: Unless specified as a leap year (366 days), always use 365 days for yearly calculations.

Question 5. Sazia took a loan of Rs. 500 from a Bank for 6 months and paid Rs. 95 every month. Find out:
a) How much amount was paid by Sazia to the bank after 6 months?
b) Find out the Interest paid by Sazia?
Answer:
a) Monthly installment = Rs. 95
Number of months = 6
Total amount paid = \(95 \times 6 =\) Rs. 570

b) Principal amount (loan taken) = Rs. 500
Total amount paid = Rs. 570
Interest paid = Total amount paid - Principal amount
Interest = \(570 - 500 =\) Rs. 70
In simple words: Multiply the monthly payment by 6 to find the total money returned, then subtract the original loan amount to find the extra money paid as interest.

Exam Tip: Interest is always calculated as the difference between the total amount returned and the original loan amount.

Question 6. See the rate list given below and answer to the following questions:

a) Find out the cost of 10kg of Iron and 6kg of plastic.
Answer:
Cost of 1 kg of iron = Rs. 50
Cost of 10 kg of iron = \(10 \times 50 =\) Rs. 500
Cost of 1 kg of plastic = Rs. 14
Cost of 6 kg of plastic = \(6 \times 14 =\) Rs. 84
Total cost = \(500 + 84 =\) Rs. 584
In simple words: Multiply the quantity of each item by its price per kg, then add both amounts together.

Exam Tip: Calculate each item's cost separately before adding them up.

b) What cost more 3kg of Newspaper or 4kg of waste paper and by how much?
Answer:
Cost of 1 kg of newspaper = Rs. 6
Cost of 3 kg of newspaper = \(3 \times 6 =\) Rs. 18
Cost of 1 kg of waste paper = Rs. 5
Cost of 4 kg of waste paper = \(4 \times 5 =\) Rs. 20
Comparing the two: Rs. 20 (waste paper) > Rs. 18 (newspaper)
Difference = \(20 - 18 =\) Rs. 2
Therefore, 4kg of waste paper costs more by Rs. 2.
In simple words: Find the total price for both options and compare which number is greater.

Exam Tip: Always write down the final comparison statement clearly along with the exact difference amount.

c) What is the total cost of 9kg waste paper, 30kg of iron and 12kg of plastic?
Answer:
Cost of 9 kg of waste paper = \(9 \times 5 =\) Rs. 45
Cost of 30 kg of iron = \(30 \times 50 =\) Rs. 1500
Cost of 12 kg of plastic = \(12 \times 14 =\) Rs. 168
Total cost = \(45 + 1500 + 168 =\) Rs. 1713
In simple words: Multiply each given weight by its rate from the table and add all three products together.

Exam Tip: Align your numbers properly by place value when performing the final addition.