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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)
53
×
47
(2)
22
×
18
(3)
51
×
49
(4)
88
×
92
(5)
2
32
(6)
103
×
97
(7)
82
×
78
(8)
2
52
(9)
33
×
27
(10)
93
×
87
(11)
2
23
(12)
2
67
©2026 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
53
×
47
2
2
=
(
50
＋
3
)
(
50
−
3
)
=
50
−
3
=
2500
−
9
=
2491
(2)
22
×
18
2
2
=
(
20
＋
2
)
(
20
−
2
)
=
20
−
2
=
400
−
4
=
396
(3)
51
×
49
2
2
=
(
50
＋
1
)
(
50
−
1
)
=
50
−
1
=
2500
−
1
=
2499
(4)
88
×
92
2
2
=
(
90
−
2
)
(
90
＋
2
)
=
90
−
2
=
8100
−
4
=
8096
(5)
2
32
2
2
2
=
(
30
＋
2
)
=
30
＋
2
×
30
×
2
＋
2
=
900
＋
120
＋
4
=
1024
(6)
103
×
97
2
2
=
(
100
＋
3
)
(
100
−
3
)
=
100
−
3
=
10000
−
9
=
9991
(7)
82
×
78
2
2
=
(
80
＋
2
)
(
80
−
2
)
=
80
−
2
=
6400
−
4
=
6396
(8)
2
52
2
2
2
=
(
50
＋
2
)
=
50
＋
2
×
50
×
2
＋
2
=
2500
＋
200
＋
4
=
2704
(9)
33
×
27
2
2
=
(
30
＋
3
)
(
30
−
3
)
=
30
−
3
=
900
−
9
=
891
(10)
93
×
87
2
2
=
(
90
＋
3
)
(
90
−
3
)
=
90
−
3
=
8100
−
9
=
8091
(11)
2
23
2
2
2
=
(
20
＋
3
)
=
20
＋
2
×
20
×
3
＋
3
=
400
＋
120
＋
9
=
529
(12)
2
67
2
2
2
=
(
70
−
3
)
=
70
−
2
×
70
×
3
＋
3
=
4900
−
420
＋
9
=
4489