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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)
97
×
103
(2)
87
×
93
(3)
2
51
(4)
2
29
(5)
69
×
71
(6)
2
33
(7)
2
72
(8)
2
31
(9)
19
×
21
(10)
2
87
(11)
2
41
(12)
63
×
57
©2026 数学クラブ http://sugaku.club/
月 日( )
【解答例】
(1)
97
×
103
2
2
=
(
100
−
3
)
(
100
+
3
)
=
100
−
3
=
10000
−
9
=
9991
(2)
87
×
93
2
2
=
(
90
−
3
)
(
90
+
3
)
=
90
−
3
=
8100
−
9
=
8091
(3)
2
51
2
2
2
=
(
50
+
1
)
=
50
+
2
×
50
×
1
+
1
=
2500
+
100
+
1
=
2601
(4)
2
29
2
2
2
=
(
30
−
1
)
=
30
−
2
×
30
×
1
+
1
=
900
−
60
+
1
=
841
(5)
69
×
71
2
2
=
(
70
−
1
)
(
70
+
1
)
=
70
−
1
=
4900
−
1
=
4899
(6)
2
33
2
2
2
=
(
30
+
3
)
=
30
+
2
×
30
×
3
+
3
=
900
+
180
+
9
=
1089
(7)
2
72
2
2
2
=
(
70
+
2
)
=
70
+
2
×
70
×
2
+
2
=
4900
+
280
+
4
=
5184
(8)
2
31
2
2
2
=
(
30
+
1
)
=
30
+
2
×
30
×
1
+
1
=
900
+
60
+
1
=
961
(9)
19
×
21
2
2
=
(
20
−
1
)
(
20
+
1
)
=
20
−
1
=
400
−
1
=
399
(10)
2
87
2
2
2
=
(
90
−
3
)
=
90
−
2
×
90
×
3
+
3
=
8100
−
540
+
9
=
7569
(11)
2
41
2
2
2
=
(
40
+
1
)
=
40
+
2
×
40
×
1
+
1
=
1600
+
80
+
1
=
1681
(12)
63
×
57
2
2
=
(
60
+
3
)
(
60
−
3
)
=
60
−
3
=
3600
−
9
=
3591