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©2025 数学クラブ http://sugaku.club/
月 日（ ）
● 次の計算をしなさい
[1C1-00]
(1)
68
×
72
(2)
2
78
(3)
2
89
(4)
2
72
(5)
2
82
(6)
47
×
53
(7)
102
×
98
(8)
62
×
58
(9)
2
68
(10)
2
21
(11)
43
×
37
(12)
68
×
72
©2025 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
68
×
72
2
2
=
(
70
−
2
)
(
70
＋
2
)
=
70
−
2
=
4900
−
4
=
4896
(2)
2
78
2
2
2
=
(
80
−
2
)
=
80
−
2
×
80
×
2
＋
2
=
6400
−
320
＋
4
=
6084
(3)
2
89
2
2
2
=
(
90
−
1
)
=
90
−
2
×
90
×
1
＋
1
=
8100
−
180
＋
1
=
7921
(4)
2
72
2
2
2
=
(
70
＋
2
)
=
70
＋
2
×
70
×
2
＋
2
=
4900
＋
280
＋
4
=
5184
(5)
2
82
2
2
2
=
(
80
＋
2
)
=
80
＋
2
×
80
×
2
＋
2
=
6400
＋
320
＋
4
=
6724
(6)
47
×
53
2
2
=
(
50
−
3
)
(
50
＋
3
)
=
50
−
3
=
2500
−
9
=
2491
(7)
102
×
98
2
2
=
(
100
＋
2
)
(
100
−
2
)
=
100
−
2
=
10000
−
4
=
9996
(8)
62
×
58
2
2
=
(
60
＋
2
)
(
60
−
2
)
=
60
−
2
=
3600
−
4
=
3596
(9)
2
68
2
2
2
=
(
70
−
2
)
=
70
−
2
×
70
×
2
＋
2
=
4900
−
280
＋
4
=
4624
(10)
2
21
2
2
2
=
(
20
＋
1
)
=
20
＋
2
×
20
×
1
＋
1
=
400
＋
40
＋
1
=
441
(11)
43
×
37
2
2
=
(
40
＋
3
)
(
40
−
3
)
=
40
−
3
=
1600
−
9
=
1591
(12)
68
×
72
2
2
=
(
70
−
2
)
(
70
＋
2
)
=
70
−
2
=
4900
−
4
=
4896