25×0.35+2.4×1.5
=2.5×3.5+（2.5-1）×1.5
=2.5×3.5+2.5×1.5-1×1.5
=2.5×（3.5+1.5）-1.5
=2.5×5-1.5
=12.5-1.5
=11