0.79×2.6+7.9×0.74
=0.79×2.6+[(0.79×10)×(7.4÷10)]
=0.79×2.6+[0.79×10×7.4÷10]
=0.79×2.6+0.79×7.4
=0.79×(2.6+7.4)
=0.79×10=7.9