Question

口算我最棒！ 3× 1 7 × 1 3 =	5 8 × 3 5 =	1 4 × 3 8 ×4=
( 1 7 + 1 6 )×42=	3 4 × 1 6 =	2 5 ×9+ 2 5 =
3 4 ×5- 3 4 =	( 1 3 + 1 2 )×6=	16× 1 3 ×6=

Answer 1

分析：①②③⑤⑨约分计算；④⑥⑦⑧运用乘法分配律简算．

解答：解：①3×

1

7

×

1

3

=

1

7

；            ②

5

8

×

3

5

=

3

8

；          ③

1

4

×

3

8

×4=

3

8

；
④（

1

7

+

1

6

）×42=13；            ⑤

3

4

×

1

6

=

1

8

；         ⑥

2

5

×9+

2

5

=4；
⑦

3

4

×5-

3

4

=3；                  ⑧（

1

3

+

1

2

）×6=5；    ⑨16×

1

3

×6=32．

点评：完成此题，应认真分析数据，根据数字特点，灵活简算．