问题 解答题
4
7
13
×2
1
7
+4
2
7
×4
7
13
+6
4
7
×4
7
13

61
1
5
×
5
6
+71
1
6
×
6
7
+91
1
8
×
8
9
答案

(1)4

7
13
×2
1
7
+4
2
7
×4
7
13
+6
4
7
×4
7
13

=4

7
13
×(2
1
7
+4
2
7
+6
4
7
),

=4

7
13
×13,

=(4+

7
13
)×13,

=4×13+

7
13
×13,

=52+7,

=59;

(2)61

1
5
×
5
6
+71
1
6
×
6
7
+91
1
8
×
8
9

=(60+

6
5
)×
5
6
+(70+
7
6
)×
6
7
+(90+
9
8
)×
8
9

=60×

5
6
+
6
5
×
5
6
+70×
6
7
+
7
6
×
6
7
+90×
8
9
+
9
8
×
8
9

=50+1+60+1+80+1,

=(50+60+80)+(1+1+1),

=190+3,

=193.

判断题
问答题 简答题