ІІ ЧАСТИНА. I. Тисяча » 37-38

37. 500 – 300 = 200; 600 – 200 = 400; 400 + 300 = 700; 800 + 200 = 1000; 300 + 300 = 600; 400 + 400 = 800; 600 – 400 = 200; 500 – 100 = 400. 38. 4 • 7 = 28; 7 • 8 = 56; 7 • 7 = 49; 3 • 9 = 27; 6 • 9 = 54; 28 : 7 = 4; 63 : 7 = 9; 64 : 8 = 8; 18 : 9 = 2; 45 : 5 = 9.