(25/2) * (32/10) * (1/4) = (25*32) / (2*10*4) =(25*4) / 10 = 100/10=10
90 * (72-14.4)/3.6 = 90 * ((720-144)/36)=90*(20-4)=90*16=1440
77/9 - 21/8 - 1.375 = 77/9 - 21/8 - 11/8 = 77/9 - 32/8 = 77/9 - 4 = 41/9