1. Adding & Subtracting in Scientific Notation Exponents are SAME 1.) If exponents same, add or subtract the coefficients and keep the power of 10. Examples: (3.5 x 10 5 ) (8.9 x 10 -3 ) + (2.3 x 10 5 ) - (6.3 x 10 -3 ) 5.8 x 10 5 2.6 x 10 -3 2.) If needed, adjust decimal and exponent so answer is in scientific notation.

2. Exponents are DIFFERENT 1.) If exponents different, change to the largest exponent. Example: (3.5 x 10 6 ) + (2.3 x 10 5 ) 0.23 x 10 6 2.) Add or subtract coefficients and keep the common base. (3.5 x 10 6 ) + (0.23 x 10 6 ) 3.73 x 10 6 3.) If needed, adjust decimal and exponent so answer is in scientific notation. Change the term with smaller exponent to match the larger exponent. Exponent increased. Decimal decreased. Adding & Subtracting in Scientific Notation

3. Example: (3.5 x 10 6 ) + (2.3 x 10 5 ) 0.23 x 10 6 Change the term with smaller exponent to match the larger exponent. Exponent increased. Decimal decreased. Adding & Subtracting in Scientific Notation When making the exponent larger, the decimal will move LEFT to make the coefficient smaller, and keep the coefficient and power of 10 balanced.