We need to add 1.45 x 10^8 and 3.9 x 10^7.
Please see..
We have given numbers in scientific form.
<em>We can't add the decimal numbers in front, because those numbers are being multiplied with 10 exponents and the exponents of 10's are not same.</em>
<em>So, we always convert the exponents of 10 as same.</em>
<em>1.45 x 10^8 could be converted to 14.5 x 10^7 to get exponent of 10 as 7 as other number 3.9 x 10^7 also has exponent of 10 as 7.</em>
<em>After this step we can just add the 14.5 and 3.9 and put × 10^7 with it.</em>
So, first correct step is:
<h3>
2. Convert 1.45 x 108 to 14.5 x 107.</h3>