10.3×99+10.3=10.3×（99+1）=1030
3.7×2.5+0.3×2.5=2.5×（3.7+0.3）=10
0.125×（8+0.8）=0.125×8+0.125×0.8=1+0.1=1.1
1.6×7.8×1.25=0.8×2×7.8×1.25=0.8×1.25×2×7.8=1×2×7.8=15.6