Напишу по действиям
а)
1)2+1/3 = 6/3 + 1/3 = 7/3
2) 1 + 1/(7/3) = 1 + 3/7 = 7/7+3/7 = 10/7
3) 1/(10/7) = 1*7/10 = 7/10
б)
1) 2 + 1/2 = 4/2 + 1/2 = 5/2
2) 2 + 1/(5/2) = 2+ 2/5 = 10/5 + 2/5 = 12/5
3) 1/(12/5) = 1* 5/12 = 5/12
в)
1) 3 + 1/3 = 9/3 + 1/3 = 10/3
2) 3 + 1/(10/3) = 3 + 3/10 = 33/10
3) 1/(33/10) = 1 * 10/33 = 10/33