Let smallest number = x.
Then, x + x + 1 + x + 2 + x + 3 + x + 4 = 170

Correct Option: C

Let smallest number = x.
Then, x + x + 1 + x + 2 + x + 3 + x + 4 = 170
⇒ 5x + 10 = 170
⇒ x = 160 / 5
⇒ x = 32

∴ product of smallest and largest number = 32 x 36
= 1152

Let the two consecutive odd numbers be 2x+1 and 2x + 3 .

Correct Option: C

Let the two consecutive odd numbers be 2x+1 and 2x + 3 .
∴ Difference = ( 2x + 3 )² - ( 2x + 1 )²
= ( 2x + 3 + 2x + 1 )( 2x + 3 - 2x - 1 )
=( 4x + 4 ) x 2
= 8 (x + 1)
whis is exactly divisible by 8.

156 + 844 = 1000

Correct Option: A

9856 x 156 + 9856 x 844 = 9856 x (156 + 844)
= 9856 x 1000
= 9856000

6674 x 625 = 6674 x (5)⁴

Correct Option: D

6674 x 625 = 6674 x (5)⁴
= 6674 x (10⁴/2⁴
= 66740000/16 = 4171250

999 = 1000 -1

Correct Option: B

Exp.= 9998 x 999
= 9998 x (1000-1)
= 9998 x 1000 - 9998 x 1
= 9998000 - 9998 = 9988002