Odpowiedź :
(6,25-2 1/2):2 1/7-1=(6 1/4-2 2/4):2 1/7-1 = 15/4*7/15-1 = 7/4 -1 = 1 3/4-1=3/4
= (6, 25 - 2,5) × 7/15 - 1 = 3 3/4 × 7/15 - 1 = 15/4 × 7/15 - 1 = 7/4 - 1 = 1, 75 - 1 = 0,75