（1）4.26+5.14+5.74+3.86

=（4.26+5.74）+（5.14+3.86）

=10+9

=19；

（2）0.2+99×0.82

=0.2+（100-1）×0.82

=0.2+100×0.82-0.82

=0.2+82-0.82

=81.38；

（3）6÷0.3-0.3÷6

=20-0.05

=19.95；

（4）1.3×[2÷（4.1-4.05）]

=1.3×[2÷0.05]

=1.3×40

=52．