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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
31
(3)
2
62
(4)
2
87
(5)
38
×
42
(6)
71
×
69
(7)
52
×
48
(8)
2
53
(9)
2
83
(10)
99
×
101
(11)
2
73
(12)
43
×
37
©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
31
2
2
2
=
(
30
+
1
)
=
30
+
2
×
30
×
1
+
1
=
900
+
60
+
1
=
961
(3)
2
62
2
2
2
=
(
60
+
2
)
=
60
+
2
×
60
×
2
+
2
=
3600
+
240
+
4
=
3844
(4)
2
87
2
2
2
=
(
90
−
3
)
=
90
−
2
×
90
×
3
+
3
=
8100
−
540
+
9
=
7569
(5)
38
×
42
2
2
=
(
40
−
2
)
(
40
+
2
)
=
40
−
2
=
1600
−
4
=
1596
(6)
71
×
69
2
2
=
(
70
+
1
)
(
70
−
1
)
=
70
−
1
=
4900
−
1
=
4899
(7)
52
×
48
2
2
=
(
50
+
2
)
(
50
−
2
)
=
50
−
2
=
2500
−
4
=
2496
(8)
2
53
2
2
2
=
(
50
+
3
)
=
50
+
2
×
50
×
3
+
3
=
2500
+
300
+
9
=
2809
(9)
2
83
2
2
2
=
(
80
+
3
)
=
80
+
2
×
80
×
3
+
3
=
6400
+
480
+
9
=
6889
(10)
99
×
101
2
2
=
(
100
−
1
)
(
100
+
1
)
=
100
−
1
=
10000
−
1
=
9999
(11)
2
73
2
2
2
=
(
70
+
3
)
=
70
+
2
×
70
×
3
+
3
=
4900
+
420
+
9
=
5329
(12)
43
×
37
2
2
=
(
40
+
3
)
(
40
−
3
)
=
40
−
3
=
1600
−
9
=
1591