CBSE Class 6 Mathematics Whole Numbers Assignment Set 07

VI - Mathematics Assignment No - 04 - Whole Nos.

Question 1. The Cost of T.V is Rs 40,000. The dealer allows a discount of Rs 7,500 on Dipawali. Find the net selling price
Answer: Cost price of the T.V = Rs 40,000
Discount allowed = Rs 7,500
Net selling price = Cost price - Discount
Net selling price = Rs 40,000 - Rs 7,500 = Rs 32,500
In simple words: Subtract the discount amount from the original price to find the final price paid.

Exam Tip: Read the question carefully to identify whether discount is added or subtracted from the cost price.

Question 2. Find the product of greatest number of 5 digits and smallest number of 4 digits
Answer: Greatest 5-digit number = 99,999
Smallest 4-digit number = 1,000
Product = \(99,999 \times 1,000 = 99,999,000\)
In simple words: Multiply the largest five-digit number by one thousand by appending three zeros.

Exam Tip: Greatest numbers are formed using digits of 9, and smallest numbers start with 1 followed by zeros.

Question 3. A bus moves at a uniform speed of 75 km/hr. How much distance will it cover in \(5\frac{1}{5}\) hour?
Answer: Speed of the bus = 75 km/hr
Time = \(5\frac{1}{5}\) hours = \(\frac{26}{5}\) hours
Distance = Speed \(\times\) Time
Distance = \(75 \times \frac{26}{5}\)
Distance = \(15 \times 26 = 390 \text{ km}\)
In simple words: Multiply the speed by the total time taken to calculate the total distance covered.

Question 4. The product of two whole numbers is zero. What can you say about the two numbers?
Answer: If the product of two whole numbers is zero, then either one of them is zero, or both of them are zero.
In simple words: To get a product of zero in multiplication, at least one of the numbers must be zero.

Exam Tip: This is based on the zero property of multiplication.

Question 5. What is that whole number which when multiplied by itself gives the same number?
Answer: Let the whole number be \(x\).
According to the question, \(x \times x = x\)
The whole numbers that satisfy this condition are 0 and 1.
(\(0 \times 0 = 0\) and \(1 \times 1 = 1\))
In simple words: Zero and one are the only numbers that remain unchanged when multiplied by themselves.

Exam Tip: Always check both 0 and 1 as they have special properties in multiplication and powers.

Question 6. Find the sum of the following numbers in two ways: \(15 + 16 + 5\)
Answer: Way 1: Grouping first two numbers using associative property
\((15 + 16) + 5\)
\(= 31 + 5\)
\(= 36\)

Way 2: Grouping last two numbers
\(15 + (16 + 5)\)
\(= 15 + 21\)
\(= 36\)
In simple words: Addition gives the same result regardless of how the numbers are grouped.

Exam Tip: This demonstrates the associative property of addition.

Question 7. Use associative property to find the product of \(14 \times 45\) [Hint: Write 14 as \(7 \times 2\), \(\therefore\) question becomes \(7 \times 2 \times 45\), now apply property]
Answer: Given expression = \(14 \times 45\)
Substitute \(14 = 7 \times 2\):
\(= 7 \times (2 \times 45)\)
Apply associative property of multiplication:
\(= 7 \times 90\)
\(= 630\)
In simple words: Break a composite number into factors to make multiplication simpler by grouping.

Exam Tip: Look for easy groupings like multiples of 10 to simplify calculations.

Question 8. Using distributive property, find the product of \(12 \times 55\) [Hint: Write 55 as \((50 + 5)\) or in any other way \(\therefore\) question becomes \(12 \times (50 + 5) \dots\)]
Answer: Given expression = \(12 \times 55\)
Write \(55 = (50 + 5)\):
\(= 12 \times (50 + 5)\)
Apply distributive property over addition \(a \times (b + c) = (a \times b) + (a \times c)\):
\(= (12 \times 50) + (12 \times 5)\)
\(= 600 + 60\)
\(= 660\)
In simple words: Distribute the multiplier over the split components of the second number.

Exam Tip: The distributive property helps break complex multiplications into mental math steps.

Question 9. Kamla purchased \(2 \text{ kg}\) full cream milk at the rate of Rs 30 per kg. and \(2\frac{1}{2} \text{ kg}\) Toned milk at the rate of Rs 25 per kg. How much money Kamla will give to the shopkeeper.
Answer: Cost of full cream milk = \(2 \times 30 = \text{Rs } 60\)
Quantity of toned milk = \(2\frac{1}{2} \text{ kg} = 2.5 \text{ kg}\)
Cost of toned milk = \(2.5 \times 25 = \text{Rs } 62.50\)
Total money to be given = Cost of full cream milk + Cost of toned milk
Total money = \(60 + 62.50 = \text{Rs } 122.50\)
In simple words: Calculate the cost of each type of milk separately and add them together.

Exam Tip: Align decimal points carefully when adding rupee amounts with paise.

Question 10. What type of number is the product of
(i) two odd numbers?
(ii) two even numbers?
(iii) an odd and an even no.?
Answer:
(i) Product of two odd numbers is always an odd number. (e.g., \(3 \times 5 = 15\))
(ii) Product of two even numbers is always an even number. (e.g., \(2 \times 4 = 8\))
(iii) Product of an odd and an even number is always an even number. (e.g., \(3 \times 4 = 12\))
In simple words: Odd times odd is odd, while even numbers always retain their evenness in multiplication.

Exam Tip: Remember these basic rules of parity for quick checking in objective questions.