Вправи 1 - 100 » 35

400 + 100 = 4 д. + 1 д. = 5 д. = 500 450 + 110 = (400 + 100) + (50 + 10) = 500 + 60 = 560 700 + 200 = 7 д. + 2 д. = 9 д. = 900 720 + 260 = (700 + 200) + (20 + 60) = 900 + 80 = 980 (150 – 90) : 10 = (150 – 50 – 40) : 10 = (100 – 40) : 10 = 60 : 10 = 6 100 – 90 : 10 = 100 – 9 = 91

Вправи 1 - 100