+223 To subtract these two numbers, you will need to make the exponents equal each other.
So let's look at the second term: 3 x 10-2
We want to change that exponent to 102. Since we're increasing the exponents by 4 powers of ten (from -2 to 2), that means we need to reduce the number on the left (3) by 4 powers of ten. So that means we divide 3 by 10 four times. 3/10 = .3 ----> .3 / 10 = .03 ----> .03 / 10 = .003 ----> .003 / 10 = .0003 (You can do this process more easily by moving the decimal point to the left 4 times).
Now you have 0.0003 x 102
Now just subtract 0.0003 from 9 to get 8.9997 x 102
