CBSE Class 4 Mathematics The Junk Seller Assignment Set 01

Q.1- A tea seller earns Rs.20 per day. Find out how much he will earn in:
a) A week
b) 10 days
c) A month
d) A year
Answer:
Earnings per day = Rs. 20
a) A week (7 days):
Total earning = \(20 \times 7 = \text{Rs. } 140\)
b) 10 days:
Total earning = \(20 \times 10 = \text{Rs. } 200\)
c) A month (taking 30 days):
Total earning = \(20 \times 30 = \text{Rs. } 600\)
d) A year (365 days):
Total earning = \(20 \times 365 = \text{Rs. } 7300\)
In simple words: Multiply the daily earning by the number of days to find the total amount.

Exam Tip: Remember standard conversions: 1 week = 7 days, 1 month = 30 days (unless specified), and 1 year = 365 days.

Q.2- Shanti took a loan of Rs.3000 from a bank for one year and returned Rs.3800 after one year. What is the interest paid by her?
Answer:
Total amount returned = Rs. 3800
Principal amount taken as loan = Rs. 3000
Interest paid = Total amount returned - Principal amount
Interest = \(3800 - 3000 = \text{Rs. } 800\)
In simple words: Interest is the extra money paid over the borrowed amount, found by subtracting the original loan from the total returned amount.

Exam Tip: Interest = Total Money Paid Back - Money Borrowed.

Q.3- Ratan took a loan of Rs.300 from a bank for 7 months and paid Rs.48 every month. Aman took a loan of Rs.300 from a person named Chunnilal and paid Rs.350 after 7 months.
Find out:
a) How much amount will be paid by Ratan?
b) Find out the interest paid by Ratan?
c) Who has paid more (Ratan/Aman)?
Answer:
a) Monthly payment by Ratan = Rs. 48
Number of months = 7
Total amount paid by Ratan = \(48 \times 7 = \text{Rs. } 336\)

b) Principal amount taken by Ratan = Rs. 300
Interest paid by Ratan = Total amount paid - Principal amount
Interest = \(336 - 300 = \text{Rs. } 36\)

c) Total amount paid by Aman = Rs. 350
Total amount paid by Ratan = Rs. 336
Comparing both amounts, \(350 > 336\), so Aman has paid more.
In simple words: Multiply Ratan's monthly installment by 7 to get his total payment, then compare it directly with Aman's total payment of Rs. 350.

Exam Tip: Read carefully whether the payment is given as a monthly installment or as a lump sum total at the end.

Q.4- Look at Kirans rate list and answer the following questions:

a) How much will Kiran pay for 42 kg newspaper?
b) How much Kiran has to pay for 22 kg plastic?
c) Find out the cost of 2 kg Brass?
Answer:
a) Rate of newspaper per kg = Rs. 5
Quantity = 42 kg
Total cost = \(42 \times 5 = \text{Rs. } 210\)

b) Rate of plastic per kg = Rs. 10
Quantity = 22 kg
Total cost = \(22 \times 10 = \text{Rs. } 220\)

c) Rate of brass per kg = Rs. 180
Quantity = 2 kg
Total cost = \(180 \times 2 = \text{Rs. } 360\)
In simple words: Multiply the given weight of each item by its respective rate from the table.

Exam Tip: Always pick the correct rate for each material from the given rate list table before multiplying.

Q.5- Solve it using Lattice multiplication.
a) 23×13
b) 36×21
Answer:
a) For \(23 \times 13\):
Set up a \(2 \times 2\) grid with digits 2, 3 on top and 1, 3 on the side. Multiply each digit and add along the diagonals.
Diagonal sums: Unit digit = 9, Tens digit = \(6 + 3 = 9\), Hundreds digit = 2.
Result = 299

b) For \(36 \times 21\):
Set up a \(2 \times 2\) grid with digits 3, 6 on top and 2, 1 on the side. Multiply each digit and add along the diagonals.
Diagonal sums: Unit digit = 6, Tens digit = \(3 + 12 = 15\) (write 5, carry 1), Hundreds digit = \(6 + 1 = 7\).
Result = 756
In simple words: Draw a box divided into cells with diagonal lines, multiply individual digits, and sum the numbers along the diagonals to get the product.

Exam Tip: Pay careful attention to diagonal carry-overs in lattice multiplication grids.

Q.6- What cost more and by how much?
Burger Rs.60.50
Pizza Rs.75.45
Answer:
Cost of Pizza = Rs. 75.45
Cost of Burger = Rs. 60.50
Since \(75.45 > 60.50\), Pizza costs more.
Difference in cost = \(75.45 - 60.50 = \text{Rs. } 14.95\)
In simple words: Compare the two prices and subtract the smaller price from the larger price to find the difference.

Exam Tip: Align the decimal points properly when subtracting amounts of money.