Решение по действиям:
1) 19 1/6 + 43,75=19 1/6 + 43 3/4 = 62+ 2/12+9/12 = 62 11/12
2) 62 11/12 * 5/6 = 755/12*5/6 = 3775/72 = 52 31/72
3) 26,8 -23 3/7 = 26 4/5 - 23 3/7 = 3+(4/5-3/7)= 3 +(28/35-15/35)=3 13/35
4) 3 13/35 :6/35 = 118/35 : 6/35 = 118/6 = 19 5/6
5) 52 31/72 - 19 5/6 = 33 +(31/72 - 5/6) = 33 +(31/72-60/72) = 33 29/72