( 7/8 - 13/20) + 9/10 = ( 35/40 - 26/40) + 9/10 = 9/40 + 9/10 = 9/40 + 36/40 = 45/40 = 9/8 = 1целая 1/8
( 7/8 - 13/20) + 9/10 = ( 35/40 - 26/40) + 9/10 = 9/40 + 9/10 = 9/40 + 36/40 = 45/40 = 9/8 = 1целая 1/8