Help me solve a few mathematical recursive equations, clever calculation, crab! To clever calculation Oh~ 1、15.72-4.38÷2.4 2、7.2×2.02÷2.4 3、9.8×25

Help me solve a few mathematical recursive equations, clever calculation, crab! To clever calculation Oh~ 1、15.72-4.38÷2.4 2、7.2×2.02÷2.4 3、9.8×25

1、15.72-4.38÷2.4=15.72-4.38÷0.3÷8=15.72-14.6÷8=15.72-1.7=14.022、7.2×2.02÷2.4=2.4×3×2.02÷2.4=3×2.02×(2.4÷2.4)=6.06×1=6.063、9.8×25=(10-0.2)×25=10×25-0.2×25=250-5=245