Case A: 12 - 8 = 4
Case B: 13 - 9 = 4 (1 was added to both the minuend & the subtrahend!)
Case C: 11 - 7 = 4 (1 was subtracted from both the minuend & the subtrahend!)
Notice how the difference remained exactly the same in each case!
Case A: 14 - 3 = 11
Case B: 15 - 4 = 11 (1 was added to both the minuend & the subtrahend!)
Case C: 16 - 5 = 11 (2 was added to both the minuend & the subtrahend!)
Case D: 13 - 2 = 11 (1 was subtracted from both the minuend & the subtrahend!)
Case E: 12 - 1 = 11 (2 was subtracted from both the minuend & the subtrahend!)
Case F: 14.5 - 3.5 = 11 (0.5 was added to both the minuend & the subtrahend!)
Case G: 13.5 - 2.5 = 11 (0.5 was subtracted from both the minuend & the subtrahend!)
Case A: -7 - (-6) = -1
Case B: -6 - (-5) = -1 (1 was added to both the minuend & the subtrahend!)
Case C: -5 - (-4) = -1 (2 was added to both the minuend & the subtrahend!)
Case D: -8 - (-7) = -1 (1 was subtracted from both the minuend & the subtrahend!)
Case E: -9 - (-8) = -1 (2 was subtracted from both the minuend & the subtrahend!)
Case F: (-7 + i) - (-6 + i) = -1 (i was added to both the minuend & the subtrahend!)
Case G: (-7 - i) - (-6 - i) = -1 (i was subtracted from both the minuend & the subtrahend!)
Case H: (-6 + i) - (-5 + i) = -1 (1 + i was added to both the minuend & the subtrahend!)
Case I: (-8 - i) - (-7 - i) = -1 (1 + i was subtracted from both the minuend & the subtrahend!)
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© Derek Cumberbatch