1/4+(5/8-3/10)×1/13=1/4+(25/40-12/40)×1/13=1/4+13/40×1/13=10/40+1/40=11/40原式=5/8×4/3+5/8×4/3=2×(5/8×4/3)=2×5/6=5/3
8/13×5/4-125%×3/13-3/13×5/4=8/13×5/4-5/4×3/13-3/13×5/4=(8/13-3/13-3/13)×5/4=2/13)×5/4=5/26