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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)
42
×
38
(2)
2
59
(3)
2
43
(4)
63
×
57
(5)
2
42
(6)
2
59
(7)
2
22
(8)
51
×
49
(9)
73
×
67
(10)
42
×
38
(11)
18
×
22
(12)
2
49
©2026 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
42
×
38
2
2
=
(
40
＋
2
)
(
40
−
2
)
=
40
−
2
=
1600
−
4
=
1596
(2)
2
59
2
2
2
=
(
60
−
1
)
=
60
−
2
×
60
×
1
＋
1
=
3600
−
120
＋
1
=
3481
(3)
2
43
2
2
2
=
(
40
＋
3
)
=
40
＋
2
×
40
×
3
＋
3
=
1600
＋
240
＋
9
=
1849
(4)
63
×
57
2
2
=
(
60
＋
3
)
(
60
−
3
)
=
60
−
3
=
3600
−
9
=
3591
(5)
2
42
2
2
2
=
(
40
＋
2
)
=
40
＋
2
×
40
×
2
＋
2
=
1600
＋
160
＋
4
=
1764
(6)
2
59
2
2
2
=
(
60
−
1
)
=
60
−
2
×
60
×
1
＋
1
=
3600
−
120
＋
1
=
3481
(7)
2
22
2
2
2
=
(
20
＋
2
)
=
20
＋
2
×
20
×
2
＋
2
=
400
＋
80
＋
4
=
484
(8)
51
×
49
2
2
=
(
50
＋
1
)
(
50
−
1
)
=
50
−
1
=
2500
−
1
=
2499
(9)
73
×
67
2
2
=
(
70
＋
3
)
(
70
−
3
)
=
70
−
3
=
4900
−
9
=
4891
(10)
42
×
38
2
2
=
(
40
＋
2
)
(
40
−
2
)
=
40
−
2
=
1600
−
4
=
1596
(11)
18
×
22
2
2
=
(
20
−
2
)
(
20
＋
2
)
=
20
−
2
=
400
−
4
=
396
(12)
2
49
2
2
2
=
(
50
−
1
)
=
50
−
2
×
50
×
1
＋
1
=
2500
−
100
＋
1
=
2401