zad 18 oblicz a 2/3-1/2 kreska ulamkowa 3/4-2/3 b 6/5-2/7 kreska ulamkowa 2/5+2/3 c 1 1/2-2,75 kreska ulamkowa 1 5/6-2 1/12 d 1,25+27/8 kreska ulamkowa 1 5/16+3/8 e 1 5/6-0,625 kreska ulamkowa 4/13-25/39

Rozwiązanie w załączniku 

a) (2/3 - 1/2)/(3/4 -2/3) = (4/6 - 3/6)/(9/12 - 8/12) = (1/6)/(1/12) = 1/6 : 1/12 =  = 1/6 * 12 = 2 b)(6/5 - 2/7)/(2/5 + 2/3) = (42/35 - 10/35)/(6/15 + 10/15) = (32/35)/(16/15) =  = 32/35 : 16/15 = 32/35 * 15/16 = 2 * 3 : 7 = 6/7 c) (1 1/2 - 2,75)/(1 5/6 - 2 1/12) = (1 1/2 - 2 3/4)/(1 10/12 - 2 1/12) =  = (1 2/4 - 2 3/4)/(1 10/12 - 1 13/12) = (- 1 1/4)/(- 3/12) = (- 5/4)/(- 3/12) =  = - 5/4 : - 3/12 = - 5/4 * - 12/3 =  5/4 * 4 = 5 d) (1,25 + 27/8)/(1 5/16 + 3/8) = (1 1/4 + 3 3/8)/(1 5/16 + 6/16) =  = (1 2/8 + 3 3/8)/(1 11/16) = (4 5/8)/(27/16) = 37/8 : 27/16 =  = 37/8 * 16/27 = 37 * 2/27 = 74/27 = 2 20/27 e) (1 5/6 - 0,625)/(4/13 - 25/39) = (1 5/6 - 5/8)/(12/39 - 25/39) =  = (1 20/24 - 15/24)/(- 13/39) = (44/24 - 15/24)/(- 13/39) = 29/24 : - 13/39 =  = 29/24 : - 1/3 = 29/24 * - 3 = - 29/8 = - 3 5/8