Updated By SaraNextGen

On April 21, 2024, 11:35 AM

Question 1:

Which of the following will not represent zero?

(a) 1 + 0 (b) 0 × 0

(c)   (d) 

Answer:

(a) 1 + 0 = 1

It does not represent zero.

(b) 0 × 0 = 0

It represents zero.

(c) 

It represents zero.

(d) 

It represents zero.

Question 2:

If the product of two whole numbers is zero, can we say that one or both of them will be zero? Justify through examples.

Answer:

If the product of 2 whole numbers is zero, then one of them is definitely zero.

For example, 0 × 2 = 0 and 17 × 0 = 0

If the product of 2 whole numbers is zero, then both of them may be zero.

0 × 0 = 0

However, 2 × 3 = 6

(Since numbers to be multiplied are not equal to zero, the result of the product will also be non-zero.)

Question 3:

If the product of two whole numbers is 1, can we say that one of both of them will be 1? Justify through examples.

Answer:

If the product of 2 numbers is 1, then both the numbers have to be equal to 1.

For example, 1 × 1 = 1

However, 1 × 6 = 6

Clearly, the product of two whole numbers will be 1 in the situation when both numbers to be multiplied are 1.

Question 4:

Find using distributive property:

(a) 728 × 101 (b) 5437 × 1001

(c) 824 × 25 (d) 4275 × 125

(e) 504 × 35

Answer:

(a) 728 × 101= 728 × (100 + 1)

= 728 × 100 + 728 × 1

= 72800 + 728 = 73528

(b) 5437 × 1001 = 5437 × (1000 + 1)

= 5437 × 1000 + 5437 × 1

= 5437000 + 5437 = 5442437

(c) 824 × 25 = (800 + 24) × 25

= (800 + 25 − 1) × 25

= 800 × 25 + 25 × 25 − 1 × 25

= 20000 + 625 − 25

= 20000 + 600 = 20600

(d) 4275 × 125 = (4000 + 200 + 100 − 25) × 125

= 4000 × 125 + 200 × 125 + 100 × 125 − 25 × 125

= 500000 + 25000 + 12500 − 3125

= 534375

(e) 504 × 35 = (500 + 4) × 35

= 500 × 35 + 4 × 35

= 17500 + 140 = 17640

Question 5:

Study the pattern:

1 × 8 + 1 = 9 1234 × 8 + 4 = 9876

12 × 8 + 2 = 98 12345 × 8 + 5 = 98765

123 × 8 + 3 = 987

Write the next two steps. Can you say how the pattern works?

(Hint: 12345 = 11111 + 1111 + 111 + 11 + 1).

Answer:

123456 × 8 + 6 = 987648 + 6 = 987654

1234567 × 8 + 7 = 9876536 + 7 = 9876543

Yes, the pattern works.

As 123456 = 111111 + 11111 + 1111 + 111 + 11 + 1,

123456 × 8 = (111111 + 11111 + 1111 + 111 + 11 + 1) × 8

= 111111 × 8 + 11111 × 8 + 1111 × 8 + 111 × 8 + 11 × 8 + 1 × 8

= 888888 + 88888 + 8888 + 888 + 88 + 8 = 987648

123456 × 8 + 6 = 987648 + 6 = 987654