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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)
82
×
78
(2)
98
×
102
(3)
2
29
(4)
62
×
58
(5)
2
63
(6)
22
×
18
(7)
62
×
58
(8)
2
51
(9)
92
×
88
(10)
2
27
(11)
2
37
(12)
2
83
©2026 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
82
×
78
2
2
=
(
80
＋
2
)
(
80
−
2
)
=
80
−
2
=
6400
−
4
=
6396
(2)
98
×
102
2
2
=
(
100
−
2
)
(
100
＋
2
)
=
100
−
2
=
10000
−
4
=
9996
(3)
2
29
2
2
2
=
(
30
−
1
)
=
30
−
2
×
30
×
1
＋
1
=
900
−
60
＋
1
=
841
(4)
62
×
58
2
2
=
(
60
＋
2
)
(
60
−
2
)
=
60
−
2
=
3600
−
4
=
3596
(5)
2
63
2
2
2
=
(
60
＋
3
)
=
60
＋
2
×
60
×
3
＋
3
=
3600
＋
360
＋
9
=
3969
(6)
22
×
18
2
2
=
(
20
＋
2
)
(
20
−
2
)
=
20
−
2
=
400
−
4
=
396
(7)
62
×
58
2
2
=
(
60
＋
2
)
(
60
−
2
)
=
60
−
2
=
3600
−
4
=
3596
(8)
2
51
2
2
2
=
(
50
＋
1
)
=
50
＋
2
×
50
×
1
＋
1
=
2500
＋
100
＋
1
=
2601
(9)
92
×
88
2
2
=
(
90
＋
2
)
(
90
−
2
)
=
90
−
2
=
8100
−
4
=
8096
(10)
2
27
2
2
2
=
(
30
−
3
)
=
30
−
2
×
30
×
3
＋
3
=
900
−
180
＋
9
=
729
(11)
2
37
2
2
2
=
(
40
−
3
)
=
40
−
2
×
40
×
3
＋
3
=
1600
−
240
＋
9
=
1369
(12)
2
83
2
2
2
=
(
80
＋
3
)
=
80
＋
2
×
80
×
3
＋
3
=
6400
＋
480
＋
9
=
6889