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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)
53
×
47
(2)
99
×
101
(3)
2
48
(4)
2
63
(5)
69
×
71
(6)
2
31
(7)
59
×
61
(8)
29
×
31
(9)
101
×
99
(10)
2
28
(11)
2
43
(12)
37
×
43
©2026 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
53
×
47
2
2
=
(
50
＋
3
)
(
50
−
3
)
=
50
−
3
=
2500
−
9
=
2491
(2)
99
×
101
2
2
=
(
100
−
1
)
(
100
＋
1
)
=
100
−
1
=
10000
−
1
=
9999
(3)
2
48
2
2
2
=
(
50
−
2
)
=
50
−
2
×
50
×
2
＋
2
=
2500
−
200
＋
4
=
2304
(4)
2
63
2
2
2
=
(
60
＋
3
)
=
60
＋
2
×
60
×
3
＋
3
=
3600
＋
360
＋
9
=
3969
(5)
69
×
71
2
2
=
(
70
−
1
)
(
70
＋
1
)
=
70
−
1
=
4900
−
1
=
4899
(6)
2
31
2
2
2
=
(
30
＋
1
)
=
30
＋
2
×
30
×
1
＋
1
=
900
＋
60
＋
1
=
961
(7)
59
×
61
2
2
=
(
60
−
1
)
(
60
＋
1
)
=
60
−
1
=
3600
−
1
=
3599
(8)
29
×
31
2
2
=
(
30
−
1
)
(
30
＋
1
)
=
30
−
1
=
900
−
1
=
899
(9)
101
×
99
2
2
=
(
100
＋
1
)
(
100
−
1
)
=
100
−
1
=
10000
−
1
=
9999
(10)
2
28
2
2
2
=
(
30
−
2
)
=
30
−
2
×
30
×
2
＋
2
=
900
−
120
＋
4
=
784
(11)
2
43
2
2
2
=
(
40
＋
3
)
=
40
＋
2
×
40
×
3
＋
3
=
1600
＋
240
＋
9
=
1849
(12)
37
×
43
2
2
=
(
40
−
3
)
(
40
＋
3
)
=
40
−
3
=
1600
−
9
=
1591