Addition and subtraction using scientific notation can be done easily when the number being subtracted or added has the same exponent base. For example, if one wants to add 5.66 x 10^4 + 9.99 x 10^2, there is one step that needs to be taken. Moving the decimal two places to the left of 9.99, the result is 0.0999 x10^4. Our exponents are now both 10^4 and the addition can simply be 5.66 +0.0999.
. x10^4 can be added to the end of the product.
