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©2026 数学クラブ http://sugaku.club/
月 日( )
● 次の計算をしなさい
[1C1-00]
(1)
2
89
(2)
2
53
(3)
2
83
(4)
2
83
(5)
83
×
77
(6)
2
82
(7)
83
×
77
(8)
53
×
47
(9)
19
×
21
(10)
2
69
(11)
38
×
42
(12)
2
68
©2026 数学クラブ http://sugaku.club/
月 日( )
【解答例】
(1)
2
89
2
2
2
=
(
90
−
1
)
=
90
−
2
×
90
×
1
+
1
=
8100
−
180
+
1
=
7921
(2)
2
53
2
2
2
=
(
50
+
3
)
=
50
+
2
×
50
×
3
+
3
=
2500
+
300
+
9
=
2809
(3)
2
83
2
2
2
=
(
80
+
3
)
=
80
+
2
×
80
×
3
+
3
=
6400
+
480
+
9
=
6889
(4)
2
83
2
2
2
=
(
80
+
3
)
=
80
+
2
×
80
×
3
+
3
=
6400
+
480
+
9
=
6889
(5)
83
×
77
2
2
=
(
80
+
3
)
(
80
−
3
)
=
80
−
3
=
6400
−
9
=
6391
(6)
2
82
2
2
2
=
(
80
+
2
)
=
80
+
2
×
80
×
2
+
2
=
6400
+
320
+
4
=
6724
(7)
83
×
77
2
2
=
(
80
+
3
)
(
80
−
3
)
=
80
−
3
=
6400
−
9
=
6391
(8)
53
×
47
2
2
=
(
50
+
3
)
(
50
−
3
)
=
50
−
3
=
2500
−
9
=
2491
(9)
19
×
21
2
2
=
(
20
−
1
)
(
20
+
1
)
=
20
−
1
=
400
−
1
=
399
(10)
2
69
2
2
2
=
(
70
−
1
)
=
70
−
2
×
70
×
1
+
1
=
4900
−
140
+
1
=
4761
(11)
38
×
42
2
2
=
(
40
−
2
)
(
40
+
2
)
=
40
−
2
=
1600
−
4
=
1596
(12)
2
68
2
2
2
=
(
70
−
2
)
=
70
−
2
×
70
×
2
+
2
=
4900
−
280
+
4
=
4624