［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
21
(2)
2
77
(3)
22
×
18
(4)
2
77
(5)
78
×
82
(6)
48
×
52
(7)
2
72
(8)
2
38
(9)
41
×
39
(10)
2
81
(11)
2
42
(12)
42
×
38
©2026 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
2
21
2
2
2
=
(
20
＋
1
)
=
20
＋
2
×
20
×
1
＋
1
=
400
＋
40
＋
1
=
441
(2)
2
77
2
2
2
=
(
80
−
3
)
=
80
−
2
×
80
×
3
＋
3
=
6400
−
480
＋
9
=
5929
(3)
22
×
18
2
2
=
(
20
＋
2
)
(
20
−
2
)
=
20
−
2
=
400
−
4
=
396
(4)
2
77
2
2
2
=
(
80
−
3
)
=
80
−
2
×
80
×
3
＋
3
=
6400
−
480
＋
9
=
5929
(5)
78
×
82
2
2
=
(
80
−
2
)
(
80
＋
2
)
=
80
−
2
=
6400
−
4
=
6396
(6)
48
×
52
2
2
=
(
50
−
2
)
(
50
＋
2
)
=
50
−
2
=
2500
−
4
=
2496
(7)
2
72
2
2
2
=
(
70
＋
2
)
=
70
＋
2
×
70
×
2
＋
2
=
4900
＋
280
＋
4
=
5184
(8)
2
38
2
2
2
=
(
40
−
2
)
=
40
−
2
×
40
×
2
＋
2
=
1600
−
160
＋
4
=
1444
(9)
41
×
39
2
2
=
(
40
＋
1
)
(
40
−
1
)
=
40
−
1
=
1600
−
1
=
1599
(10)
2
81
2
2
2
=
(
80
＋
1
)
=
80
＋
2
×
80
×
1
＋
1
=
6400
＋
160
＋
1
=
6561
(11)
2
42
2
2
2
=
(
40
＋
2
)
=
40
＋
2
×
40
×
2
＋
2
=
1600
＋
160
＋
4
=
1764
(12)
42
×
38
2
2
=
(
40
＋
2
)
(
40
−
2
)
=
40
−
2
=
1600
−
4
=
1596