Question

Multiply by suitable arrangement : -4 X 128 X(-250)

Answer 1

(a x b) x c , or (a x c) x b so (-4 x 128) x -250 =128000
Hope this will help u

Answer 2

Just apply integers rule like

_x_
So ans wll be

_4x_250x128
=1000x128
=128000