PLIS HELP ile to jest 1 2/7+1/4= 1 3/4+3 3/5= 5 2/3-3 2/5= 7 4/8-5 3/4= 15*4 2/3 3 2/3=, 2 2/7=, 2 5/9=. 2- 1 1/2*2/5=

1 i 2/7 + 1/4= = 1 i 8/28 + 7/28= = 1 i 15/28 1 i 3/4 + 3 i 3/5= = 1 i 15/20 + 3 i 12/20= = 4 i 27/20= = 5 i 7/20 5 i 2/3 - 3 i 2/5= = 5 i 10/15 - 3 i 6/15= = 2 i 4/15 7 i 4/8 - 5 i 3/4= = 7 i 4/8 - 5 i 6/8 = = 6 i 12/8 - 5 i 6/8= = 1 i 6/8= = 1 i 3/4 15 * 4 i 2/3= = 15 * 14/3= = 5 * 14/1 = = 70/1= = 70 2 - 1 i 1/2 * 2/5= = 2 - 3/2 * 2/5= = 2 - 3/1 * 1/5= = 2 - 3/5= = 1 i 5/5 - 3/5= = 1 i 2/5