CBSE Class 4 Mathematics The Junk Seller Assignment Set 02

Q1. Find the product using lattice multiplication:
a) 37 \times 12
Answer: Set up a \(2 \times 2\) grid for 37 and 12.
Multiply each digit:
Row 1: \(3 \times 1 = 03\), \(3 \times 2 = 06\)
Row 2: \(7 \times 1 = 07\), \(7 \times 2 = 14\)
Add along the diagonals from right to left:
Units diagonal: \(4 = 4\)
Tens diagonal: \(6 + 1 + 7 = 14\) (write 4, carry 1 to the next diagonal)
Hundreds diagonal: \(3 + 0 + 0 + 1 \text{ (carry)} = 4\)
Thousands diagonal: \(0 = 0\)
Product = 444
In simple words: Draw a 2 by 2 box, multiply each number separately, and add diagonally to get 444.

Exam Tip: Always make sure to write single-digit products with a leading zero (e.g., \(3 \times 2 = 06\)) in lattice boxes to keep diagonal additions correct.

b) 29 \times 19
Answer: Set up a \(2 \times 2\) grid for 29 and 19.
Multiply each digit:
Row 1: \(2 \times 1 = 02\), \(2 \times 9 = 18\)
Row 2: \(9 \times 1 = 09\), \(9 \times 9 = 81\)
Add along the diagonals from right to left:
Units diagonal: \(1 = 1\)
Tens diagonal: \(8 + 8 + 9 = 25\) (write 5, carry 2)
Hundreds diagonal: \(2 + 1 + 0 + 2 \text{ (carry)} = 5\)
Thousands diagonal: \(0 = 0\)
Product = 551
In simple words: Multiply digits in the lattice grid cells and sum the diagonals to find the total product 551.

Exam Tip: Be careful with carries when summing numbers along the diagonal paths.

c) 45 \times 56
Answer: Set up a \(2 \times 2\) grid for 45 and 56.
Multiply each digit:
Row 1: \(4 \times 5 = 20\), \(4 \times 6 = 24\)
Row 2: \(5 \times 5 = 25\), \(5 \times 6 = 30\)
Add along the diagonals from right to left:
Units diagonal: \(0 = 0\)
Tens diagonal: \(4 + 3 + 5 = 12\) (write 2, carry 1)
Hundreds diagonal: \(2 + 0 + 2 + 1 \text{ (carry)} = 5\)
Thousands diagonal: \(2 = 2\)
Product = 2520
In simple words: Fill the lattice boxes with partial products and add the diagonals to get 2520.

Exam Tip: Double-check your multiplication table facts inside each cell.

Q2. Convert into Rupees:
a) 1456p = Rs. 14.56
Answer: Since 100 paise = Rs. 1, divide by 100.
\(1456 \div 100 = \text{Rs. } 14.56
In simple words: Divide paise by 100 by placing a decimal point two digits from the right.

Exam Tip: Remember to put the Rs. symbol in front of your final answer.

b) 56093p = Rs. 560.93
Answer: \(56093 \div 100 = \text{Rs. } 560.93
In simple words: Shift the decimal point two places to the left.

Exam Tip: Count two digits from the right before inserting the decimal point.

c) 254 p = Rs. 2.54
Answer: \(254 \div 100 = \text{Rs. } 2.54
In simple words: 254 paise makes 2 rupees and 54 paise.

Exam Tip: Always keep two decimal places for money.

d) 1500 p = Rs. 15.00
Answer: \(1500 \div 100 = \text{Rs. } 15.00
In simple words: 1500 paise is exactly 15 rupees.

Exam Tip: Zeros after the decimal point indicate exact rupees with no extra paise.

Q3. Convert into paise:
a) Rs. 2.05 = 205 p
Answer: Multiply by 100: \(2.05 \times 100 = 205\text{ p}
In simple words: Remove the decimal point to convert rupees into paise.

Exam Tip: Multiplying by 100 shifts the decimal point two places to the right.

b) Rs. 475.68 = 47568 p
Answer: \(475.68 \times 100 = 47568\text{ p}
In simple words: 475 rupees and 68 paise equals 47568 paise in total.

c) Re. 0.95 = 95 p
Answer: \(0.95 \times 100 = 95\text{ p}
In simple words: 95 paise is written as Re. 0.95 or 95 p.
Exam Tip: 'Re.' is used for 1 rupee, while 'Rs.' is used for amounts greater than 1.

d) Rs. 500.89 = 50089 p
Answer: \(500.89 \times 100 = 50089\text{ p}
In simple words: Multiply the rupee amount by 100 to get paise.

Exam Tip: Do not forget to append 'p' at the end of the answer.

Q4. Add the following:
a) Rs. 564.45 and Rs. 95.75
Answer: Align the decimal points and add:
\(564.45\)
\(+ 095.75\)
\(\overline{660.20}\)
Total = Rs. 660.20
In simple words: Line up the numbers by their decimal points and add them up to get Rs. 660.20.

Exam Tip: Always align decimal points vertically before adding money amounts.

b) Rs. 87.56, Rs. 100.25 and Rs. 7.85
Answer: Align the decimal points and add:
\(087.56\)
+ \(100.25\)
+ \(007.85\)
\(\overline{195.66}\)
Total = Rs. 195.66
In simple words: Sum the three given monetary amounts carefully column by column.

Exam Tip: Add zeroes as placeholders for alignment if needed.

c) Re. 0.79, Rs. 95.50 and Rs. 15.85
Answer: Align the decimal points and add:
\(00.79\)
+ \(95.50\)
+ \(15.85\)
\(\overline{112.14}\)
Total = Rs. 112.14
In simple words: Combine 79 paise, 95.50 rupees, and 15.85 rupees to get Rs. 112.14.

Exam Tip: Re. 0.79 is the same as Rs. 0.79.

Q5. Find the product using expanded notation:
a) 567 \times 9
Answer: Expand 567 into hundreds, tens, and units:
\(567 = 500 + 60 + 7\)
Multiply each expanded part by 9:
\((500 \times 9) + (60 \times 9) + (7 \times 9)\)
\(= 4500 + 540 + 63\)
\(= 5103
In simple words: Break 567 into 500, 60, and 7, multiply each by 9, and add the results.

Exam Tip: Expanded notation makes mental multiplication much easier and clearer.

b) 2763 \times 6
Answer: Expand 2763:
\(2763 = 2000 + 700 + 60 + 3\)
Multiply each part by 6:
\((2000 \times 6) + (700 \times 6) + (60 \times 6) + (3 \times 6)\)
\(= 12000 + 4200 + 360 + 18\)
\(= 16578
In simple words: Multiply each place value of 2763 by 6 and sum up all parts.

Exam Tip: Keep your addition neat to avoid carrying mistakes at the end.

c) 9134 \times 9
Answer: Expand 9134:
\(9134 = 9000 + 100 + 30 + 4\)
Multiply each part by 9:
\((9000 \times 9) + (100 \times 9) + (30 \times 9) + (4 \times 9)\)
\(= 81000 + 900 + 270 + 36\)
\(= 82206
In simple words: Expand the number, multiply by 9 term by term, and add to get 82206.

Exam Tip: Verify each multiplication step before doing the final addition.

Q6. Fill in the blanks:
a) There are 28 25 p coins in 7 rupees.
Answer: Rs. 7 = 700 paise
Number of coins = \(700 \div 25 = 28\)
In simple words: Divide 700 paise by 25 paise to get 28 coins.

Exam Tip: Convert rupees to paise first before dividing by coin value.

b) There are 100 5p coins in 5 rupees.
Answer: Rs. 5 = 500 paise
Number of coins = \(500 \div 5 = 100\)
In simple words: Divide 500 paise by 5 paise to find 100 coins.

Exam Tip: 1 rupee contains twenty 5-paise coins; therefore, 5 rupees contain \(5 \times 20 = 100\) coins.

c) There are 20 50 p coins in 10 rupees.
Answer: Rs. 10 = 1000 paise
Number of coins = \(1000 \div 50 = 20\)
In simple words: 10 rupees divided into 50 paise coins equals 20 coins.

Exam Tip: Two 50-paise coins make 1 rupee.

d) There are 200 10p coins in 20 rupees.
Answer: Rs. 20 = 2000 paise
Number of coins = \(2000 \div 10 = 200\)
In simple words: Divide 2000 paise by 10 paise to get 200 coins.

Exam Tip: Ten 10-paise coins make 1 rupee.

e) There are 20 20p coins in 4 rupees.
Answer: Rs. 4 = 400 paise
Number of coins = \(400 \div 20 = 20\)
In simple words: Divide 400 paise by 20 paise to get 20 coins.

Exam Tip: Five 20-paise coins make 1 rupee.

Q7. Calculate the total amount of money:
a) Five Rs. 100 + Ten Rs. 50 + One Rs. 10 = Rs. 1010
Answer: \(5 \times 100 = 500\)
\(10 \times 50 = 500\)
\(1 \times 10 = 10\)
Total = \(500 + 500 + 10 = \text{Rs. } 1010
In simple words: Multiply each note count by its value and add them together to get Rs. 1010.

Exam Tip: Calculate each denomination separately before summing.

b) Three Rs. 500 + Six Rs. 100 + Two Rs. 50 = Rs. 2200
Answer: \(3 \times 500 = 1500\)
\(6 \times 100 = 600\)
\(2 \times 50 = 100\)
Total = \(1500 + 600 + 100 = \text{Rs. } 2200
In simple words: Total equals 1500 + 600 + 100 = Rs. 2200.

Exam Tip: Double multiplication sums carefully.

c) Two Rs. 20 + Ten Rs. 10 + Eight Rs. 5 = Rs. 180
Answer: \(2 \times 20 = 40\)
\(10 \times 10 = 100\)
\(8 \times 5 = 40\)
Total = \(40 + 100 + 40 = \text{Rs. } 180
In simple words: Add 40, 100, and 40 to get Rs. 180.

Exam Tip: Check your multiplication for smaller note values.

Q8. A fruit seller bought apples at Rs. 110 per kg and sold them for Rs. 125 per kg. How much money did he gain after selling 20 kg of apples?
Answer: Cost price of 1 kg of apples = Rs. 110
Selling price of 1 kg of apples = Rs. 125
Gain on 1 kg of apples = \(\text{Rs. } 125 - \text{Rs. } 110 = \text{Rs. } 15
Quantity of apples sold = 20 kg
Total gain = \(20 \times 15 = \text{Rs. } 300
In simple words: Find the profit on 1 kg (Rs. 15) and multiply by 20 kg to get a total gain of Rs. 300.

Exam Tip: You can either find total selling price minus total cost price, or profit per kg multiplied by total quantity.

Q9. Vimla bought 5 icecreams for Rs. 25, Rs. 49, Rs. 120, Rs. 35 and Rs. 150. How much money will she get back from a Rs. 500 note?
Answer: Cost of 5 icecreams = \(25 + 49 + 120 + 35 + 150\)
\(25 + 49 = 74\)
\(74 + 120 = 194\)
\(194 + 35 = 229\)
\(229 + 150 = 379\)
Total cost = Rs. 379
Amount given = Rs. 500
Money to get back = \(\text{Rs. } 500 - \text{Rs. } 379 = \text{Rs. } 121
In simple words: Add up all ice cream prices to get Rs. 379, then subtract from Rs. 500 to get Rs. 121 back.

Exam Tip: Always subtract the total bill amount from the money paid to find the change.

Q10. Vinay visited a sport shop and purchased 2 Racquets for Rs. 200 each, 3 Shuttle cocks for Rs. 15 each, 2 Table Tennis Racquets for Rs. 250 each, 6 Table Tennis Balls for Rs. 10 each, 1 Cricket Bat for Rs. 500 and a Cricket Ball for Rs. 75. Make a bill for the following items that Vinay bought and calculate the amount he had to pay.
Answer: Cost of 2 Racquets = \(2 \times 200 = \text{Rs. } 400
Cost of 3 Shuttle cocks = \(3 \times 15 = \text{Rs. } 45
Cost of 2 Table Tennis Racquets = \(2 \times 250 = \text{Rs. } 500
Cost of 6 Table Tennis Balls = \(6 \times 10 = \text{Rs. } 60
Cost of 1 Cricket Bat = \(1 \times 500 = \text{Rs. } 500
Cost of 1 Cricket Ball = \(1 \times 75 = \text{Rs. } 75
Total amount to pay = \(400 + 45 + 500 + 60 + 500 + 75 = \text{Rs. } 1580
In simple words: Calculate the cost of each item type and add them all up to make a total bill of Rs. 1580.

Exam Tip: Present itemized calculations clearly in a step-by-step format when preparing a bill.