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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
31
(2)
2
87
(3)
2
68
(4)
2
37
(5)
2
21
(6)
2
87
(7)
2
41
(8)
42
×
38
(9)
27
×
33
(10)
77
×
83
(11)
2
72
(12)
2
58
©2026 数学クラブ http://sugaku.club/
月 日( )
【解答例】
(1)
2
31
2
2
2
=
(
30
+
1
)
=
30
+
2
×
30
×
1
+
1
=
900
+
60
+
1
=
961
(2)
2
87
2
2
2
=
(
90
−
3
)
=
90
−
2
×
90
×
3
+
3
=
8100
−
540
+
9
=
7569
(3)
2
68
2
2
2
=
(
70
−
2
)
=
70
−
2
×
70
×
2
+
2
=
4900
−
280
+
4
=
4624
(4)
2
37
2
2
2
=
(
40
−
3
)
=
40
−
2
×
40
×
3
+
3
=
1600
−
240
+
9
=
1369
(5)
2
21
2
2
2
=
(
20
+
1
)
=
20
+
2
×
20
×
1
+
1
=
400
+
40
+
1
=
441
(6)
2
87
2
2
2
=
(
90
−
3
)
=
90
−
2
×
90
×
3
+
3
=
8100
−
540
+
9
=
7569
(7)
2
41
2
2
2
=
(
40
+
1
)
=
40
+
2
×
40
×
1
+
1
=
1600
+
80
+
1
=
1681
(8)
42
×
38
2
2
=
(
40
+
2
)
(
40
−
2
)
=
40
−
2
=
1600
−
4
=
1596
(9)
27
×
33
2
2
=
(
30
−
3
)
(
30
+
3
)
=
30
−
3
=
900
−
9
=
891
(10)
77
×
83
2
2
=
(
80
−
3
)
(
80
+
3
)
=
80
−
3
=
6400
−
9
=
6391
(11)
2
72
2
2
2
=
(
70
+
2
)
=
70
+
2
×
70
×
2
+
2
=
4900
+
280
+
4
=
5184
(12)
2
58
2
2
2
=
(
60
−
2
)
=
60
−
2
×
60
×
2
+
2
=
3600
−
240
+
4
=
3364