Penyelesaian : 1. 19 - 8 = 11 Jadi 8 + 11 = 19 2. 45 - 23 = 22 Jadi 23 + 22 = 45 3. 54 - 16 = 38 Jadi 38 + 16 = 54 4. 68 - 38 = 32 Jadi 32 + 36 = 68