[1,75-0,(5)]:21,5= (175/100 - 5/9) : 215/10 = (7/4 - 5/9) x 2/43 = (63/36 - 20/36) x 2/43 = 43/36 x 2/43 = 1/18 = 5/90 = 0,0(5)
[2,75-2,(6)]x14,4= [275/100 - (26-2)/9] x 144/10 = (11/4 - 24/9) x 144/10 = (11/4 - 8/3) x 144/10 =(33/12 - 32/12) x 72/5 = 1/12 x 72/5 = 6/5
