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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)
18
×
22
(2)
103
×
97
(3)
2
48
(4)
31
×
29
(5)
2
89
(6)
2
43
(7)
2
38
(8)
2
78
(9)
2
53
(10)
2
23
(11)
2
31
(12)
2
61
©2026 数学クラブ http://sugaku.club/
月 日( )
【解答例】
(1)
18
×
22
2
2
=
(
20
−
2
)
(
20
+
2
)
=
20
−
2
=
400
−
4
=
396
(2)
103
×
97
2
2
=
(
100
+
3
)
(
100
−
3
)
=
100
−
3
=
10000
−
9
=
9991
(3)
2
48
2
2
2
=
(
50
−
2
)
=
50
−
2
×
50
×
2
+
2
=
2500
−
200
+
4
=
2304
(4)
31
×
29
2
2
=
(
30
+
1
)
(
30
−
1
)
=
30
−
1
=
900
−
1
=
899
(5)
2
89
2
2
2
=
(
90
−
1
)
=
90
−
2
×
90
×
1
+
1
=
8100
−
180
+
1
=
7921
(6)
2
43
2
2
2
=
(
40
+
3
)
=
40
+
2
×
40
×
3
+
3
=
1600
+
240
+
9
=
1849
(7)
2
38
2
2
2
=
(
40
−
2
)
=
40
−
2
×
40
×
2
+
2
=
1600
−
160
+
4
=
1444
(8)
2
78
2
2
2
=
(
80
−
2
)
=
80
−
2
×
80
×
2
+
2
=
6400
−
320
+
4
=
6084
(9)
2
53
2
2
2
=
(
50
+
3
)
=
50
+
2
×
50
×
3
+
3
=
2500
+
300
+
9
=
2809
(10)
2
23
2
2
2
=
(
20
+
3
)
=
20
+
2
×
20
×
3
+
3
=
400
+
120
+
9
=
529
(11)
2
31
2
2
2
=
(
30
+
1
)
=
30
+
2
×
30
×
1
+
1
=
900
+
60
+
1
=
961
(12)
2
61
2
2
2
=
(
60
+
1
)
=
60
+
2
×
60
×
1
+
1
=
3600
+
120
+
1
=
3721