a) 0,75² - ⅚ - ½ = 9/16-⅚-½ = 9/16-⅚-3/6 = 9/16-8/6 = 27/48-64/48= -37/48
b) (0,6 - ⅙ + 0,25)² = (36/60-10/60+15/60)²=(41/60)²=1681/3600
c) ⅔ - 5/7 - (1⅓)² = ⅔-5/7-16/9 = 42/63-45/63-112/63 = -115/63 = -1 52/63
d) ⅘ - (0,75 + 1,2)² = ⅘-(3/4 + 12/10)² = ⅘-(15/20 + 24/20)² = ⅘-(39/20)² = ⅘-1521/400 = 320/400-1521/400 = -1201/400 = - 3 1/400