2. Modeling integer addition using colored counters Let yellow color represent positive integers and the red color represent the negative integers. Example : Let us find the value of 7 + (-3) Show 7 yellow (positive) counters and add 3 red (negative) counters + + + + + + + + + + + To add integers with different signs, use zero pairs. Remember + 1 – 1 = 0 Take out the zero pair (one yellow and one yellow makes a zero pair). The remainder is the answer. _ _ _
3. Integer Addition: Find (-5) + (-2) Show 5 red (negative) counters. Then add 2 red counters. Together there are 7 Red counters. So (-5) + (-2) = -7 _ _ _ _ _ _ _ _ _ _ _ _ _ _
4. Integer Addition Find (- 4) + 3. _ _ _ _ _ Show 4 Red counters and then add 3 Yellow counters. Pair the Red and Yellow counters. Remove the Zero pairs. There is one negative counter left. So (-4) + 3 = -1 + + +
5. Modeling integer subtraction using colored counters Example 1: Find 6 – 3 + + + + + + + + + + + + + + + Remember Subtraction means take away. Show 6 positive counters and take away three counters. There are 3 positive counters left. So there are 3 positive counters left. Therefore, 6 – 3 = 3
6. Integer Subtraction Example 2: Find - 6 – (-3) Show 6 red (negative) counters. Take away 3 red counters. We are left with 3 red counters. Therefore, -6 – (-3) = -3 - - - - - - - - - - - - - - -
7. Integer Subtraction Example 3: Find 6 – (-2) Show 6 positive yellow counters. Insert two zero pairs. Then take away 2 negative counters. There are 8 positive counters left. So 6 – (-2) = 8 + + + + + + + + + + + + + + - -
