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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)
2
77
(2)
2
28
(3)
2
27
(4)
19
×
21
(5)
2
43
(6)
2
28
(7)
2
31
(8)
2
71
(9)
62
×
58
(10)
2
57
(11)
71
×
69
(12)
23
×
17
©2026 数学クラブ http://sugaku.club/
月 日( )
【解答例】
(1)
2
77
2
2
2
=
(
80
−
3
)
=
80
−
2
×
80
×
3
+
3
=
6400
−
480
+
9
=
5929
(2)
2
28
2
2
2
=
(
30
−
2
)
=
30
−
2
×
30
×
2
+
2
=
900
−
120
+
4
=
784
(3)
2
27
2
2
2
=
(
30
−
3
)
=
30
−
2
×
30
×
3
+
3
=
900
−
180
+
9
=
729
(4)
19
×
21
2
2
=
(
20
−
1
)
(
20
+
1
)
=
20
−
1
=
400
−
1
=
399
(5)
2
43
2
2
2
=
(
40
+
3
)
=
40
+
2
×
40
×
3
+
3
=
1600
+
240
+
9
=
1849
(6)
2
28
2
2
2
=
(
30
−
2
)
=
30
−
2
×
30
×
2
+
2
=
900
−
120
+
4
=
784
(7)
2
31
2
2
2
=
(
30
+
1
)
=
30
+
2
×
30
×
1
+
1
=
900
+
60
+
1
=
961
(8)
2
71
2
2
2
=
(
70
+
1
)
=
70
+
2
×
70
×
1
+
1
=
4900
+
140
+
1
=
5041
(9)
62
×
58
2
2
=
(
60
+
2
)
(
60
−
2
)
=
60
−
2
=
3600
−
4
=
3596
(10)
2
57
2
2
2
=
(
60
−
3
)
=
60
−
2
×
60
×
3
+
3
=
3600
−
360
+
9
=
3249
(11)
71
×
69
2
2
=
(
70
+
1
)
(
70
−
1
)
=
70
−
1
=
4900
−
1
=
4899
(12)
23
×
17
2
2
=
(
20
+
3
)
(
20
−
3
)
=
20
−
3
=
400
−
9
=
391