What are the steps to subtract in scientific notation?

Answer 1

1. Convert the numbers so that they all have the same index for 10.
2. Calculate the subtraction for the mantissae, ignoring the powers of 10.
3. Add back the power of 10 term.
4. Adjust the power, if necessary, so that the mantissa of the answer is in the range [1, 10).

Example:

1.23*10^3 - 3.4*10^2

Convert them so that the power of 10 is 2:

12.3*10^2 - 3.4*10^2 = (12.3 - 3.4)*10^2 = 8.9*10^2.

{there is no need to adjust the power of 10).

Or

Convert them so that the power of 10 is 3: 1.23*10^2 - 0.34*10^3 = (1.23 - 0.34)*10^3 = 0.89*10^3 and now you need to adjust because the mantissa is less than 1. So 8.9*10^2.