Частина 2. Номер 123

900 – 500 = 400;

600 + 300 = 900;

150 – 70 = 80;

120 – 80 = 40;

40 + 60 = 100;

90 + 80 = 170;

800 – 1 = 799;

607 – 1 = 606.