intro 360 40 5 Addition and Subtraction with Hank Buckingham comment 260 2 35 I'm sure you realized that the two actions result in a net gain of $0. reminder Since addition involves 2 positive numbers, think about the direction you'll move on the number line. reminder 350 50 5 You've probably seen distance on a number line written as absolute value. attention 350 rectangle 50 5 The point of this isn't to practice easy problems, but to help you understand subtraction at a deeper level. attention rectangle 500 270 250 2 That's why I wrote 8-3 = 8+(-3) earlier in the lesson. What happens if a +1 and -1 combine? They add to 2 They add to 0 They add to -2 They stay the same They add to 0 reminder 360 40 I can do this because subtraction is taking away. attention rectangle 360 40 Subtraction is the same as addition of a negative! reminder 100 300 20 20 460 260 Imagine walking away from your house as addition and back towards it as subtraction. reminder 350 Using absolute value, this could also be written as 4+|-3|+7+|-2|.