When you are subtracting integers make things easy! Change all SUBTRACTION to ADDITION! Then just apply the Addition Rules!
To change a SUBTRACTION problem to an ADDITION problem, apply the KEEP FLIP CHANGE (KFC). Keep Flip Change (KFC) Apply the Keep Flip Change (KFC) to subtraction problems then apply the addition rules. This is also referred to as Add the Opposite. Once you KFC, you have an addition problem!! Remember the addition rules?? We can add on to our Addition Rules to include Subtraction. When we are adding or subtracting integers the FIRST thing we do is look to see if it is addition or subtraction. If it is a subtraction problem we KFC. After we KFC we follow the Addition rules check the signs. Are they the same? Then we Add & Keep. Are they different? Then we subtract and ask. Let's try some subtraction problems.
6 – 4 = ? KFC to get 6 + –4 = ? Check signs. They are different so we SUBTRACT AND ASK Subtract 4 from 6 to get 2. Now ASK ... What is there more of? There is MORE positive so we keep the positive sign. 6 – 4 = 2 -2 - 9 = ?
KFC to get -2 + 9 = ? Check signs. They are different so we SUBTRACT AND ASK Subtract 2 from 9 to get 7. Now ASK ... What is there more of? There is MORE negative so we keep the negative sign. -2 - 9 = -7 3 - (-8) = ?
KFC to get 3 + 8 = ? Check signs. They are the same so we ADD AND KEEP the sign Add 3 and 8 to get 11. Keep the positive sign. 3 - (-8) = 11 |
ADDITION RULES
ADDITION AND SUBTRACTION RULES
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