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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
29
(2)
19
×
21
(3)
47
×
53
(4)
79
×
81
(5)
2
38
(6)
2
71
(7)
2
41
(8)
2
79
(9)
2
42
(10)
41
×
39
(11)
102
×
98
(12)
2
47
©2026 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
2
29
2
2
2
=
(
30
−
1
)
=
30
−
2
×
30
×
1
＋
1
=
900
−
60
＋
1
=
841
(2)
19
×
21
2
2
=
(
20
−
1
)
(
20
＋
1
)
=
20
−
1
=
400
−
1
=
399
(3)
47
×
53
2
2
=
(
50
−
3
)
(
50
＋
3
)
=
50
−
3
=
2500
−
9
=
2491
(4)
79
×
81
2
2
=
(
80
−
1
)
(
80
＋
1
)
=
80
−
1
=
6400
−
1
=
6399
(5)
2
38
2
2
2
=
(
40
−
2
)
=
40
−
2
×
40
×
2
＋
2
=
1600
−
160
＋
4
=
1444
(6)
2
71
2
2
2
=
(
70
＋
1
)
=
70
＋
2
×
70
×
1
＋
1
=
4900
＋
140
＋
1
=
5041
(7)
2
41
2
2
2
=
(
40
＋
1
)
=
40
＋
2
×
40
×
1
＋
1
=
1600
＋
80
＋
1
=
1681
(8)
2
79
2
2
2
=
(
80
−
1
)
=
80
−
2
×
80
×
1
＋
1
=
6400
−
160
＋
1
=
6241
(9)
2
42
2
2
2
=
(
40
＋
2
)
=
40
＋
2
×
40
×
2
＋
2
=
1600
＋
160
＋
4
=
1764
(10)
41
×
39
2
2
=
(
40
＋
1
)
(
40
−
1
)
=
40
−
1
=
1600
−
1
=
1599
(11)
102
×
98
2
2
=
(
100
＋
2
)
(
100
−
2
)
=
100
−
2
=
10000
−
4
=
9996
(12)
2
47
2
2
2
=
(
50
−
3
)
=
50
−
2
×
50
×
3
＋
3
=
2500
−
300
＋
9
=
2209