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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
61
(2)
51
×
49
(3)
71
×
69
(4)
2
33
(5)
2
57
(6)
2
62
(7)
2
37
(8)
23
×
17
(9)
2
49
(10)
2
68
(11)
2
49
(12)
92
×
88
©2026 数学クラブ http://sugaku.club/
月 日( )
【解答例】
(1)
2
61
2
2
2
=
(
60
+
1
)
=
60
+
2
×
60
×
1
+
1
=
3600
+
120
+
1
=
3721
(2)
51
×
49
2
2
=
(
50
+
1
)
(
50
−
1
)
=
50
−
1
=
2500
−
1
=
2499
(3)
71
×
69
2
2
=
(
70
+
1
)
(
70
−
1
)
=
70
−
1
=
4900
−
1
=
4899
(4)
2
33
2
2
2
=
(
30
+
3
)
=
30
+
2
×
30
×
3
+
3
=
900
+
180
+
9
=
1089
(5)
2
57
2
2
2
=
(
60
−
3
)
=
60
−
2
×
60
×
3
+
3
=
3600
−
360
+
9
=
3249
(6)
2
62
2
2
2
=
(
60
+
2
)
=
60
+
2
×
60
×
2
+
2
=
3600
+
240
+
4
=
3844
(7)
2
37
2
2
2
=
(
40
−
3
)
=
40
−
2
×
40
×
3
+
3
=
1600
−
240
+
9
=
1369
(8)
23
×
17
2
2
=
(
20
+
3
)
(
20
−
3
)
=
20
−
3
=
400
−
9
=
391
(9)
2
49
2
2
2
=
(
50
−
1
)
=
50
−
2
×
50
×
1
+
1
=
2500
−
100
+
1
=
2401
(10)
2
68
2
2
2
=
(
70
−
2
)
=
70
−
2
×
70
×
2
+
2
=
4900
−
280
+
4
=
4624
(11)
2
49
2
2
2
=
(
50
−
1
)
=
50
−
2
×
50
×
1
+
1
=
2500
−
100
+
1
=
2401
(12)
92
×
88
2
2
=
(
90
+
2
)
(
90
−
2
)
=
90
−
2
=
8100
−
4
=
8096