a) [12½ - (3⅓)]:¹⁹/₁₂= [25/2 - 10/3] : 19/12 = [75/6 - 20/6] : 19/12 = 55/6 : 19/12 = 55/6 * 12/19 = 660/114 = 5⁹⁰/₁₁₄ = 5¹⁵/₁₉
b) 1¾(⅜+1,25-0,75)= 1¾(³/₈ + 5/4 - 3/4) = 1¾(13/8 - 3/4) = 1¾ * 7/8 = 7/4 * 7/8 = 49/32 = 1¹⁷/₃₂
c)3¼-2*0,25 13/4 - 0,5 1⁵/₈
______________ = _______________ = _____ =
2⅓-2*⅓+3,5*2¼ 7/3 - 2/3 + 6³/₁₀ -3³/₁₀
= 13/8 : (-33/10) = 13/8 * (-10/33) = - 65/132
