用简便方法算1.25×（0.8+0.4）=? 4.89×99+4.89= ?

1.25×（0.8+0.4）=1.25×0.8+1.25×0.4=1+0.5=1.5
4.89×99+4.89=4.89×（99+1）=489
（14.7+5.6）÷7=14.7÷7+5.6÷7=2.1+0.8=2.9
46÷0.8-20.8这题是46÷0.8-2÷0.8或者46÷0.8-22÷0.8
如果是46÷0.8-22÷0.8,那么
46÷0.8-22÷0.8=（46-22）÷0.8=24÷0.8=30
其他的计算方法同理
46÷0.8-2÷0.8=（46-2）÷0.8=44÷0.8=55
若题目没错,46÷0.8-20.8=48÷0.8-2÷0.8-20.8=60-2.5-20.8=36.7