## NCERT Exercise 2.2 Solution class 6 math

Question (1) Find the sum by suitable rearrangement:

(a) 837 + 208 + 363

**Solution**

Given, 837 + 208 + 363

Since, whole numbers are closed under addition,

Hence, after rearranging the above expression, we get

837 + 363 + 208

= (837 + 363) + 208

= 1200 + 208 = 1408

Thus, **Answer** = 1408

(b) 1962 + 453 + 1538 + 647

**Solution**

Given, 1962 + 453 + 1538 + 647

Since, whole numbers are closed under addition,

Hence, after rearranging the above expression, we get

1962 + 1538 + 453 + 647

= (1962 + 1538) + (453 + 647)

= 3500 + 1100 = 4600

Thus, **Answer** = 4600

Question (2) Find the product by suitable rearrangement:

(a) 2 × 1768 × 50

**Solution**

Given, 2 × 1768 × 50

Since, whole numbers are closed under multiplication,

Hence, after rearranging the above expression, we get

= 2 × 50 × 1768

= (2 × 50) × 1768

= 100 × 1768

= 176800

Thus, **Answer** = 176800

(b) 4 × 166 × 125

**Solution**

Given, 4 × 166 × 125

Since, whole numbers are closed under multiplication,

Hence, after rearranging the above expression, we get

4 × 125 × 166

= (4 × 125) × 166

= 500 × 166

= 83000

Thus, **Answer** = 83000

(c) 8 × 291 × 125

Given, 8 × 291 × 125

Since, whole numbers are closed under multiplication,

Hence, after rearranging the above expression, we get

8 × 125 × 291

= (8 × 125) × 291

= 1000 × 291

= 291000

Thus, **Answer** = 291000

(d) 625 × 279 × 16

**Answer**

**Method: 1**

Given, 625 × 279 × 16

By rearranging the given expression, we get

625 × 16 × 279

By using distributive and associative property the above expression can be written as

(600 + 20 + 5) × 16 × 279

= [(600 + 20 + 5) × 16] × 279

= [(600 × 16) + (20 × 16) + (5 × 16)] × 279

= [9600 + 320 + 80] × 279

= [9600 + (320 + 80)] × 279

= [9600 + 400] × 279

= 1000 × 279

= 279000

Thus, **Answer** = 279000

**Method: 2**

Given, 625 × 279 × 16

By rearranging the given expression, we get

625 × 16 × 279

By using associative property, the above expression can be written as

(625 × 16) × 279

= 1000 × 279

= 279000

Thus, **Answer** = 279000

(e) 285 × 5 × 60

**Solution**

Given, 285 × 5 × 60

Since, whole numbers are closed under multiplication, thus by rearranging the given expression, we get

285 × (5 × 60)

= 285 × 300

Again using distributive property to the above expression, we get

285 × (3 × 100)

= (285 × 3) × 100

= 855 × 100

= 85500

Thus, **Answer** = 85,500

(f) 125 × 40 × 8 × 25

**Solution**

Given, 125 × 40 × 8 × 25

By using associative property, we get

= (125 × 40) × (8 × 25)

= 500 × 200

= 1,00,000

Thus, **Answer** = 1,00,000