ЗАДАЧІ НА ПОВТОРЕННЯ » 55
1/4 : –21/4 = 1/4 • –4/9 = –1/9; 1/4 • –9/4 = –9/16; 1/4 + (–4/9) = (9 - 16)/36 = –7/36; 1/4 – (–4/9) = (9 + 16)/36 = 25/36; –9/13 : –91/1 = 9/13 • 1/91 = 9/1183; –9/13 • –91/1 = 63; –9/13 + (–91) = –919/13; –9/13 – (–91) = 904/13.