ІІ ЧАСТИНА. I. Тисяча » 70-71

70. 700 – 500 = 200; 400 + 400 = 800; 800 + 20 + 1 = 821; 500 + 20 + 5 = 525; 900 + 30 = 930; 600 + 40 = 640; 200 + 2 = 202; 400 + 4 = 404. 71. 600 + 200 = 800; 900 + 80 = 980; 800 + 30 + 2 = 832; 1000 – 900 = 100; 500 + 3 = 503; 400 + 10 + 7 = 417.