1.)7 + 2 (3 + 9) = 7 + 2(3) + 2 (9)
2.)8 * (2 * 4) = (8 * 2) * 4
3.) (9 + 6) + (-5) = 9 + (6 + (-5))
4.) 75 + 30 = 15 (5 + 2)

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