〔常见错误〕

（1） 1 + 3.8× 1 + 4.2× 1

3 3 3

=  1 + 3.8 + 4.2× 1

 3  3

= 8 1 × 1

3 3

= 2 7 ．

9

（2）9.8×6.8 + 4 1 ×6.8 - 6.8

5

= 4 1 ×6.8

5

= 14×6.8

= 95.2。

（3）4.6×9 1 + 9.2×4 2 ×9 1

5 5 5

=4.6×9.2+4.4×9.2+9.2

=（4.6×4.4）×9.2+9.2

=186.208+9.2

=195.408。