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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)
47
×
53
(3)
42
×
38
(4)
2
69
(5)
2
32
(6)
2
87
(7)
53
×
47
(8)
2
33
(9)
2
41
(10)
41
×
39
(11)
2
31
(12)
97
×
103
©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)
47
×
53
2
2
=
(
50
−
3
)
(
50
＋
3
)
=
50
−
3
=
2500
−
9
=
2491
(3)
42
×
38
2
2
=
(
40
＋
2
)
(
40
−
2
)
=
40
−
2
=
1600
−
4
=
1596
(4)
2
69
2
2
2
=
(
70
−
1
)
=
70
−
2
×
70
×
1
＋
1
=
4900
−
140
＋
1
=
4761
(5)
2
32
2
2
2
=
(
30
＋
2
)
=
30
＋
2
×
30
×
2
＋
2
=
900
＋
120
＋
4
=
1024
(6)
2
87
2
2
2
=
(
90
−
3
)
=
90
−
2
×
90
×
3
＋
3
=
8100
−
540
＋
9
=
7569
(7)
53
×
47
2
2
=
(
50
＋
3
)
(
50
−
3
)
=
50
−
3
=
2500
−
9
=
2491
(8)
2
33
2
2
2
=
(
30
＋
3
)
=
30
＋
2
×
30
×
3
＋
3
=
900
＋
180
＋
9
=
1089
(9)
2
41
2
2
2
=
(
40
＋
1
)
=
40
＋
2
×
40
×
1
＋
1
=
1600
＋
80
＋
1
=
1681
(10)
41
×
39
2
2
=
(
40
＋
1
)
(
40
−
1
)
=
40
−
1
=
1600
−
1
=
1599
(11)
2
31
2
2
2
=
(
30
＋
1
)
=
30
＋
2
×
30
×
1
＋
1
=
900
＋
60
＋
1
=
961
(12)
97
×
103
2
2
=
(
100
−
3
)
(
100
＋
3
)
=
100
−
3
=
10000
−
9
=
9991