解:
36×2.57+1.2×22.9
=1.2×30×2.57+1.2×22.9
=1.2×77.1+1.2×22.9
=1.2×(77.1+22.9)
=1.2×100
=120
36×2.57+1.2×22.9
=12x3x2.57+12x2.29
=12x7.71+12x2.29
=12x(7.71+2.29)
=12x10
=120
乘法分配律是一种简算定律:两个数的和与一个数相乘,可以先把它们分别与这个数相乘,再相加,得数不变,这叫做分配律。
原式=1.2×30×2.57+1.2×22.9
=1.2×77.1+1.2×22.9
=1.2×(77.1+22.9)
=1.2×100
=120
=1.2×30×2.57+1.2×22.9
=1.2×30×(2.5+0.07)+1.2×22.9
=1.2×(75+2.1+22.9)
=1.2×100
=120
36×2.57+1.2*22.9
=1.2×30×2.57+1.2×22.9
=1.2×(30×2.57+22.9)
=1.2×100
=120