［文字サイズの変更］
▼
▲
©2026 数学クラブ http://sugaku.club/
月 日（ ）
● 次の計算をしなさい
[1C1-00]
(1)
2
41
(2)
91
×
89
(3)
33
×
27
(4)
2
21
(5)
51
×
49
(6)
77
×
83
(7)
88
×
92
(8)
17
×
23
(9)
33
×
27
(10)
2
42
(11)
2
77
(12)
2
27
©2026 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
2
41
2
2
2
=
(
40
＋
1
)
=
40
＋
2
×
40
×
1
＋
1
=
1600
＋
80
＋
1
=
1681
(2)
91
×
89
2
2
=
(
90
＋
1
)
(
90
−
1
)
=
90
−
1
=
8100
−
1
=
8099
(3)
33
×
27
2
2
=
(
30
＋
3
)
(
30
−
3
)
=
30
−
3
=
900
−
9
=
891
(4)
2
21
2
2
2
=
(
20
＋
1
)
=
20
＋
2
×
20
×
1
＋
1
=
400
＋
40
＋
1
=
441
(5)
51
×
49
2
2
=
(
50
＋
1
)
(
50
−
1
)
=
50
−
1
=
2500
−
1
=
2499
(6)
77
×
83
2
2
=
(
80
−
3
)
(
80
＋
3
)
=
80
−
3
=
6400
−
9
=
6391
(7)
88
×
92
2
2
=
(
90
−
2
)
(
90
＋
2
)
=
90
−
2
=
8100
−
4
=
8096
(8)
17
×
23
2
2
=
(
20
−
3
)
(
20
＋
3
)
=
20
−
3
=
400
−
9
=
391
(9)
33
×
27
2
2
=
(
30
＋
3
)
(
30
−
3
)
=
30
−
3
=
900
−
9
=
891
(10)
2
42
2
2
2
=
(
40
＋
2
)
=
40
＋
2
×
40
×
2
＋
2
=
1600
＋
160
＋
4
=
1764
(11)
2
77
2
2
2
=
(
80
−
3
)
=
80
−
2
×
80
×
3
＋
3
=
6400
−
480
＋
9
=
5929
(12)
2
27
2
2
2
=
(
30
−
3
)
=
30
−
2
×
30
×
3
＋
3
=
900
−
180
＋
9
=
729