1 9/10×20/27+5/16÷10/24-5/9×1 7/20=

10*2/27+5/16*24/10-1/9*17/4=38/27+1/2*3/2-17/36=38/26+3/4-17/36=91/54=1 37/54≈1.7

1 9/10×20/27=19/10×20/27=19/1×2/27=19/545/16÷10/24=5/16×24/10=1/2×3/2=3/45/9×1 7/20=5/9×27/20=1/1×3/4=3/419/54+3/4-3/4=19/54