Question 914518
The other tutor's answer is wrong.  He thought you were
studying logarithms and exponentials.  If you had said 
"scientific notation" instead of " powers of ten form",
he would have known what you meant.  Here is how it's
done.  I'll do an example below:  

{{{matrix(1,3,

(matrix(12,1,The,leftmost,non-zero,digit,followed,by, a, decimal, and, the, other,digits)),

"×",

10^(

matrix(1,23,The,number,of,places,the, decimal,needs,to,be,moved,to,get,back,to,the,original,"number,", "+",if,right,"-",if,left)

)


)}}}


Here's an example like yours:

4907

We start off with the 4
<b><i>
We have 4
</b></i>
We put a decimal after the 4.
<b><i>
Now we have 4.
</b></i>
We put the rest of the digits after the decimal
<b><i>
Now we have 4.907
</b></i>
We put × next.
<b><i>
Now we have 4.907 ×
</b></i>
We put 10 next
<b><i>
Now we have 4.907 × 10
</b></i>
Next we compare 4.907 to the original number 4907 and see
that the decimal in 4.907 has to move 3 places to the right
so that it will go back to 4907 with an invisible decimal
at the end.  So we put the exponent 3 to the right and above the 10:
<b><i>
Now we have the final answer:  4907 = 4.907 × 10<sup>3</sup>.
</b></i>
------------------------------------
Edwin</pre>