A=5/9+2/15-6/9 B=2/7-3/8+4/7+1/7-5/8+5/15 C=3/5+1/15+1/57+1/3-2/9-3/4-1/36 D=1/1×2+1/2×3+1/3×4+…+1/99×100 E=1-3/1×3-3/3×5-3/5×7-…-19
Question
A=5/9+2/15-6/9
B=2/7-3/8+4/7+1/7-5/8+5/15
C=3/5+1/15+1/57+1/3-2/9-3/4-1/36
D=1/1x2+1/2x3+1/3x4+...+1/99x100
E=1-3/1x3-3/3x5-3/5x7-...-19