+11912 im sorry ! cant see the question properly ! why dont u just click the part that has to be answered ?
+11912 here im doing the fifth one ;
5a)5.4*107
=54000000.0
this is becoz 10 has the power of 7 and so there are 7 zeroes added and becoz after the point theres one digit so in the answer also theres one digit and remember the digits are counted from back and the point is also put at the end !
d)7.162*103
=7162.000
now i hope u might have understood why the point is after 3 digits becoz there are 3 digits behind the point in the q. !
i am not doing the others as i want u to try them and see ! ive done 2 of different types !
+11912 this is the second one ;(2x3y2)3
the answer is (a) becoz y2*3=6 =y6
the 2x3 will remain the same so the final answer is2x3y6
+33616 Hmm! Take care!
(2x3y2)3 means everything inside the brackets is cubed. So we have
23(x3)3(y2)3, which is 8x3*3y2*3 which is 8x9y6
Or, look at it this way:
+11912 i didnt knew that method alan and i think its the correct one ! so rebeenjalal u follew alans method ! alan thumbs up from me
+118609 Alan's method is definitely correct Rosala. I am glad that you are paying close attention and learning. 
Also, your scientific notation questions are correct but you do not need the extra 0s after the decimal point. They serve no purpose.
7162.000 is better written as 7162
