How do you add and subtract with scientific notation?

Answer 1

Suppose you have two numbers in scientific notation.

· Rename them so that the exponents (powers of 10) are the same, · add the two mantissae to form the new mantissa, and append the 10 and exponent, · if the resulting mantissa is 10 or greater then rename the mantissa and adjust the exponent accordingly.
For the first stage you may rename both numbers or either one.

For example,

3.5*10^3+ 4.5*10^4= 3.5*10^3+ 45*10^3= (3.5+45)*10^3= 48.5*10^3= 4.85*10^4
or
3.5*10^3+ 4.5*10^4= 0.35*10^4+ 4.5*10^4= (0.35+4.5)*10^4= 4.85*10^4

Answer 2

To add or subtract numbers in scientific notation, make sure the exponents are the same. If they are not, adjust one of the numbers by moving the decimal point and changing the exponent accordingly. Then, simply add or subtract the coefficients and keep the common exponent. Finally, write your answer in scientific notation by making sure the first digit is between 1 and 10 and adjusting the exponent if necessary.