Definition 4.1.2 The sum of two integers, \((a — b) + (c —d)\), is defined by the formula \((a — b) + (c —d) := (a + c)— (b + d)\). The product of two integers, \((a — b) × (c — d)\), is defined by \((a —b) × (c — d) := (ac + bd)— (ad + bc)\).
Definition 4.1.2
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Exercise 4.1.4
\(=\) { Definition 4.1.2 }
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Exercise 4.1.3
\(=\) { Definition 4.1.2 }