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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)
99
×
101
(2)
43
×
37
(3)
98
×
102
(4)
71
×
69
(5)
88
×
92
(6)
2
81
(7)
77
×
83
(8)
2
49
(9)
98
×
102
(10)
2
83
(11)
77
×
83
(12)
2
68
©2026 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
99
×
101
2
2
=
(
100
−
1
)
(
100
＋
1
)
=
100
−
1
=
10000
−
1
=
9999
(2)
43
×
37
2
2
=
(
40
＋
3
)
(
40
−
3
)
=
40
−
3
=
1600
−
9
=
1591
(3)
98
×
102
2
2
=
(
100
−
2
)
(
100
＋
2
)
=
100
−
2
=
10000
−
4
=
9996
(4)
71
×
69
2
2
=
(
70
＋
1
)
(
70
−
1
)
=
70
−
1
=
4900
−
1
=
4899
(5)
88
×
92
2
2
=
(
90
−
2
)
(
90
＋
2
)
=
90
−
2
=
8100
−
4
=
8096
(6)
2
81
2
2
2
=
(
80
＋
1
)
=
80
＋
2
×
80
×
1
＋
1
=
6400
＋
160
＋
1
=
6561
(7)
77
×
83
2
2
=
(
80
−
3
)
(
80
＋
3
)
=
80
−
3
=
6400
−
9
=
6391
(8)
2
49
2
2
2
=
(
50
−
1
)
=
50
−
2
×
50
×
1
＋
1
=
2500
−
100
＋
1
=
2401
(9)
98
×
102
2
2
=
(
100
−
2
)
(
100
＋
2
)
=
100
−
2
=
10000
−
4
=
9996
(10)
2
83
2
2
2
=
(
80
＋
3
)
=
80
＋
2
×
80
×
3
＋
3
=
6400
＋
480
＋
9
=
6889
(11)
77
×
83
2
2
=
(
80
−
3
)
(
80
＋
3
)
=
80
−
3
=
6400
−
9
=
6391
(12)
2
68
2
2
2
=
(
70
−
2
)
=
70
−
2
×
70
×
2
＋
2
=
4900
−
280
＋
4
=
4624