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 adding or subtracting decimals, you must make sure that the decimals have the same number of decimal places.

2. Steps to changing the power of 10 in scientific notation:
- Move the decimal point to the right if the power of 10 is positive to increase the power.
- Move the decimal point to the left if the power of 10 is negative to decrease the power.

3. Words that tell you to subtract include: minus, decrease, take away, reduce, diminish.