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©2020 数学クラブ http://sugaku.club/
月 日（ ）
● 次の計算をしなさい
[1C1-00]
(1)
2
38
(2)
78
×
82
(3)
2
32
(4)
81
×
79
(5)
89
×
91
(6)
59
×
61
(7)
2
58
(8)
89
×
91
(9)
2
21
(10)
47
×
53
(11)
63
×
57
(12)
2
39
©2020 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
2
38
2
2
2
=
(
40
−
2
)
=
40
−
2
×
40
×
2
＋
2
=
1600
−
160
＋
4
=
1444
(2)
78
×
82
2
2
=
(
80
−
2
)
(
80
＋
2
)
=
80
−
2
=
6400
−
4
=
6396
(3)
2
32
2
2
2
=
(
30
＋
2
)
=
30
＋
2
×
30
×
2
＋
2
=
900
＋
120
＋
4
=
1024
(4)
81
×
79
2
2
=
(
80
＋
1
)
(
80
−
1
)
=
80
−
1
=
6400
−
1
=
6399
(5)
89
×
91
2
2
=
(
90
−
1
)
(
90
＋
1
)
=
90
−
1
=
8100
−
1
=
8099
(6)
59
×
61
2
2
=
(
60
−
1
)
(
60
＋
1
)
=
60
−
1
=
3600
−
1
=
3599
(7)
2
58
2
2
2
=
(
60
−
2
)
=
60
−
2
×
60
×
2
＋
2
=
3600
−
240
＋
4
=
3364
(8)
89
×
91
2
2
=
(
90
−
1
)
(
90
＋
1
)
=
90
−
1
=
8100
−
1
=
8099
(9)
2
21
2
2
2
=
(
20
＋
1
)
=
20
＋
2
×
20
×
1
＋
1
=
400
＋
40
＋
1
=
441
(10)
47
×
53
2
2
=
(
50
−
3
)
(
50
＋
3
)
=
50
−
3
=
2500
−
9
=
2491
(11)
63
×
57
2
2
=
(
60
＋
3
)
(
60
−
3
)
=
60
−
3
=
3600
−
9
=
3591
(12)
2
39
2
2
2
=
(
40
−
1
)
=
40
−
2
×
40
×
1
＋
1
=
1600
−
80
＋
1
=
1521