1. Before you add or subtract decimals, what must you do? 2. Steps to changing the power of 10 in SN: 3. Words that tell you to subtract:
1. Before you add or subtract decimals, make sure that the decimals are lined up with each other (the decimal points are in the same place).
2. Steps to changing the power of 10 in scientific notation (SN):
a. Move the decimal point in the original number to the left or right until there is only one non-zero digit to the left of the decimal point.
b. Count the number of places you moved the decimal point and use that number as the exponent in the power of 10.
3. Words that tell you to subtract include: minus, less than, decrease, reduce, take away, minus.