1. Adding and subtracting rational numbers
7th grade math and 6th grade accelerated Math

2. Adding rational numbers
Decimals: line up your decimal points and add straight
Fractions: MUST have a common denominator
Use Least Common Multiple (LCM) to determine the denominator
Multiply the numerator and the denominator by the same number
Can be a different number for each fraction (if you have to change more than one)

3. Rules for adding Rational Numbers
1. When adding with the same sign: add (+) them together and bring the sign with you
2. When adding with different signs: subtract (-) them and take the sign of the larger number

4. Subtracting rational numbers
1. Keep, Change, Change (KCC): Keep the first number the same, change the sign, and change the sign of the second number
Positive  Negative
Negative  Positive

5. Example of adding rational number (fraction)

6. Example of subtracting rational number (fraction)