(2 1/4 - 1 1/6 * (2/7 + 3 1/7 * 1/3)) : 0,7 = 125/126
1) 3 1/7 * 1/3 = 22/7 * 1/3 = 22/21 = 1 1/21
2) 2/7 + 1 1/21 = 6/21 + 1 1/21 = 1 7/21 = 1 1/3
3) 1 1/6 * 1 1/3 = 7/6 * 4/3 = (7*2)/(3*3) = 14/9 = 1 5/9
4) 2 1/4 - 1 5/9 = 2 9/36 - 1 20/36 = 1 45/36 - 1 20/36 = 25/36
5) 25/36 : 0,7 = 25/36 : 7/10 = 25/36 * 10/7 = (25*5)/(18*7) = 125/126