You can write
1.5
⋅
10
5
=
15
⋅
10
4
15
⋅
10
4
−
8
⋅
10
4
=
(
15
−
8
)
⋅
10
4
=
7
⋅
10
4
Since the power is positive we move the dec.point 4 to the right:
=
70000
Hope it works
You use the butterfly method:
360 24
___ ___
X 100
multiply 360 by 100 to get 36000
then divide by 24 to get 1500