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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)
29
×
31
(2)
58
×
62
(3)
2
39
(4)
2
39
(5)
2
72
(6)
79
×
81
(7)
2
73
(8)
57
×
63
(9)
2
69
(10)
2
23
(11)
73
×
67
(12)
21
×
19
©2026 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
29
×
31
2
2
=
(
30
−
1
)
(
30
＋
1
)
=
30
−
1
=
900
−
1
=
899
(2)
58
×
62
2
2
=
(
60
−
2
)
(
60
＋
2
)
=
60
−
2
=
3600
−
4
=
3596
(3)
2
39
2
2
2
=
(
40
−
1
)
=
40
−
2
×
40
×
1
＋
1
=
1600
−
80
＋
1
=
1521
(4)
2
39
2
2
2
=
(
40
−
1
)
=
40
−
2
×
40
×
1
＋
1
=
1600
−
80
＋
1
=
1521
(5)
2
72
2
2
2
=
(
70
＋
2
)
=
70
＋
2
×
70
×
2
＋
2
=
4900
＋
280
＋
4
=
5184
(6)
79
×
81
2
2
=
(
80
−
1
)
(
80
＋
1
)
=
80
−
1
=
6400
−
1
=
6399
(7)
2
73
2
2
2
=
(
70
＋
3
)
=
70
＋
2
×
70
×
3
＋
3
=
4900
＋
420
＋
9
=
5329
(8)
57
×
63
2
2
=
(
60
−
3
)
(
60
＋
3
)
=
60
−
3
=
3600
−
9
=
3591
(9)
2
69
2
2
2
=
(
70
−
1
)
=
70
−
2
×
70
×
1
＋
1
=
4900
−
140
＋
1
=
4761
(10)
2
23
2
2
2
=
(
20
＋
3
)
=
20
＋
2
×
20
×
3
＋
3
=
400
＋
120
＋
9
=
529
(11)
73
×
67
2
2
=
(
70
＋
3
)
(
70
−
3
)
=
70
−
3
=
4900
−
9
=
4891
(12)
21
×
19
2
2
=
(
20
＋
1
)
(
20
−
1
)
=
20
−
1
=
400
−
1
=
399