3x2 - 27 (Factor two times)

3x2 - 27
(multiply first: remember PEMDAS)
6 - 27
(subtract)
-21

In the given mathematical value of 51, 487 to round off this number to the nearest thousand, we can elaborate the number values using the expanded form to clearly see the order position: 1.  50, 000 = ten thousands 2.  1, 000 = thousands 3.  400 = hundreds 4.  80 = tens 5.  7 = ones Now we can observe the numerical value of 51, 487 than 1, 000 is the number in which belongs to the thousands’ position hence since the nearest number is 400 the value will be 51, 000.