9856 x 156 + 9856 x 844 =?

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.

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 5 consecutive even number be A = x, B = x+2, C = x+4, D = x + 6 and E = x + 8.

According to question
x + x +2 + x + 4 + x + 6 + x + 8 = 130
? 5x + 20 = 130
? x = 22
? A = 22, E = 22 + 8 = 30.
? Multiplication of A and E = 22 x 30
= 660

There can be infinite number of rational numbers between 1 and 1000.

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

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

Let, 8888 +7777 + 666 + x = 19000
Then, 17331 + x = 19000
? x = 19000 - 17331 = 1669

Let, 4003 - x - 1599 = 716
Then, x = 4003 - 1599 - 716
= 4003 - (1599 + 716)
= 4003 - 2315
= 1688

Let 37000 - x = 36000 - 888
Then x = 37000 - 36000 + 888
= 1888