( 0,3 - 3/20) * 2 6/7 - 2/5 : 1,4 = 1/7
1) 0,3 - 3/20 = 6/20 - 3/20 = 3/20
2) 3/20 * 2 6/7 = 3/20 * 20/7 = 3/7
3) 2/5 : 1,4 = 2/5 : 7/5 = 2/7
4) 3/7 - 2/7 = 1/7
------------------------------------------
( 1,08 - 2/25) : 4/7 - 0,25 : 1/3 = 1
1) 1,08 - 2/25 = 1,08 - 8/100 = 1,08 - 0,08 = 1
2) 1 : 4/7 = 7/4
3) 0,25 : 1/3 = 1/4 : 1/3 = 3/4
4) 7/4 -3/4 = 4/4 = 1