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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)
2
28
(2)
21
×
19
(3)
2
79
(4)
2
27
(5)
61
×
59
(6)
2
51
(7)
2
72
(8)
22
×
18
(9)
99
×
101
(10)
2
33
(11)
2
33
(12)
98
×
102
©2025 数学クラブ http://sugaku.club/
月 日( )
【解答例】
(1)
2
28
2
2
2
=
(
30
−
2
)
=
30
−
2
×
30
×
2
+
2
=
900
−
120
+
4
=
784
(2)
21
×
19
2
2
=
(
20
+
1
)
(
20
−
1
)
=
20
−
1
=
400
−
1
=
399
(3)
2
79
2
2
2
=
(
80
−
1
)
=
80
−
2
×
80
×
1
+
1
=
6400
−
160
+
1
=
6241
(4)
2
27
2
2
2
=
(
30
−
3
)
=
30
−
2
×
30
×
3
+
3
=
900
−
180
+
9
=
729
(5)
61
×
59
2
2
=
(
60
+
1
)
(
60
−
1
)
=
60
−
1
=
3600
−
1
=
3599
(6)
2
51
2
2
2
=
(
50
+
1
)
=
50
+
2
×
50
×
1
+
1
=
2500
+
100
+
1
=
2601
(7)
2
72
2
2
2
=
(
70
+
2
)
=
70
+
2
×
70
×
2
+
2
=
4900
+
280
+
4
=
5184
(8)
22
×
18
2
2
=
(
20
+
2
)
(
20
−
2
)
=
20
−
2
=
400
−
4
=
396
(9)
99
×
101
2
2
=
(
100
−
1
)
(
100
+
1
)
=
100
−
1
=
10000
−
1
=
9999
(10)
2
33
2
2
2
=
(
30
+
3
)
=
30
+
2
×
30
×
3
+
3
=
900
+
180
+
9
=
1089
(11)
2
33
2
2
2
=
(
30
+
3
)
=
30
+
2
×
30
×
3
+
3
=
900
+
180
+
9
=
1089
(12)
98
×
102
2
2
=
(
100
−
2
)
(
100
+
2
)
=
100
−
2
=
10000
−
4
=
9996