Number Operations and Properties

Since the digit at hundreds place of $ 38,400 $ is $ 4 < 5 $,
Rounding of $ 38,400 $ to nearest thousand we get $ 38,000 $

Minuend is the first number in the subtraction and subtrahend is the number that is to be subtracted.
$minuend - subtrahend = difference$
$\therefore $  Option B is correct.

The given no is $8974$ for rounding for nearest 1s will see the no at
ones place it is 4 . 

It is clear that  $888+88+8+8+8=1000$
 

(D) $27012=20000+7000+0+10+2$

$8t^3$ $- 27 = (2t)$$^3$ $- (3)$$^3$
$= (2t - 3)$$[(2t)$$^2$ $+ 2t \times 3 + 3$$^2$]
$= (2t - 3)(4t$^2$ + 6t + 9)$
$\because$ $(2t - 3)(4t$$^2$ $+ 6t + 9)$
$= (2t - 3)(a + 6t + 9)$
$\Rightarrow$ $4t$$^2$ $+ 6t + 9 = (a + 6t + 9)$
$\therefore$ $a = 4t$$^2$

Expanded form of 27012 is

Expanded form of 920,831

$99 = 10 \times 9 + 9$

$72 = 10 \times 7 + 2$

The general form of any three digit number is, $abc = a \times 100 + b \times 10 + c$
So, $753 = 7 \times 100 + 5 \times 10 + 3$

The usual form: $6 \times 10 +9 = 60+9 = 69$

The general form of any two digit number is, $ab = a \times 10 + b$
So, $9 \times 10 + 0$ is in general form.