Question

用简便方法计算。

1。 6.27×3.6+37.8×0.36 2。 369×0.99+3.69 3。 （0.64+0.32）÷0.64 4。 13.5×2.5-0.35×25 5。 0.76÷0.4-0.38 6。 12.8+0.792÷0.9

Answer 1

1。 6.27×3.6+37.8×0.36
=6.27×3.6+3.78×3.6
=（6.27+3.78）×3.6
=10×3.6
=36

2。 369×0.99+3.69
=3.69×99+3.69
=3.69×（99+1）
=3.69×100
=369

3。 （0.64+0.32）÷0.64
=（0.32×2+0.32）÷0.64
=（2+1）×0.32÷0.64
=3×0.32÷0.64
=3×（0.32÷0.64）
=3×0.5
=1.5

4。 13.5×2.5-0.35×25
=1.35×25-0.35×25
=（1.35-0.35）×25
=1×25
=25

5。 0.76÷0.4-0.38
=0.76÷0.4-0.76÷2
=0.76×2.5-0.76×0.5
=0.76×（2.5-0.5）
=0.76×2
=1.52

6。 12.8+0.792÷0.9

=12.8+7.92÷9
=12.8+0.88
=13.68