7.2x5.8+0.72x42
=7.2x5.8+7.2x4.2
=7.2x(5.8+4.2)
=7.2x10
=72
7.2x5.8+0.72x42
=0.72x58+0.72x42
=0.72x(58+42)
=0.72x100
=72
7.2×5.8+0.72×42=7.2×5.8+7.2×4.2=7.2×(5.8+4.2)=7.2×10=72
7.2*5.8+0.72*42
=7.2*5.8+(0.72*10)*(42/10)
=7.2*5.8+7.2*4.2
=7.2*(5.8+4.2)
=7.2*10
=72
根据乘法的性质。