算数【応用】四則計算（小数・分数なし）
問１
5 + 3 × 7 – ( 20 – 2 × 7 ) =
- 答え
- 20
- 解き方
- 5 + 3 × 7 – ( 20 – 2 × 7 )
= 5 + 21 – ( 20 – 14 )
= 5 + 21 – 6 = 20
問２
14 + 6 × 3 – 35 ÷ 7 + 28 =
- 答え
- 55
- 解き方
- 14 + 6 × 3 – 35 ÷ 7 + 28
= 14 + 18 – 5 + 28 = 55
問３
29 + { 24 – 9 × ( 8 – 6 ) } ÷ 3 =
- 答え
- 31
- 解き方
- 29 + { 24 – 9 × ( 8 – 6 ) } ÷ 3
= 29 + ( 24 – 9 × 2 ) ÷ 3
= 29 + ( 24 – 18 ) ÷ 3
= 29 + 6 ÷ 3
= 29 + 2 = 31
問４
67 – { 10 + 16 × ( 17 – 8 ) ÷ 12 } × 3 =
- 答え
- 1
- 解き方
- 67 – { 10 + 16 × ( 17 – 8 ) ÷ 12 } × 3
= 67 – ( 10 + 16 × 9 ÷ 12 ) × 3
= 67 – ( 10 + \(\dfrac{16\ ×\ 9}{12}\) ) × 3
= 67 – ( 10 + 12 ) × 3
= 67 – 22 × 3
= 67 – 66 = 1
問５
42 – ( 65 – 9 ) ÷ ( 4 + 12 ÷ 4 ) =
- 答え
- 34
- 解き方
- 42 – ( 65 – 9 ) ÷ ( 4 + 12 ÷ 4 )
= 42 – 56 ÷ ( 4 + 3 )
= 42 – 56 ÷ 7
= 42 – 8 = 34
問６
1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 =
- 答え
- 100
- 解き方
- 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19
= ( 1 + 19 ) + ( 3 + 17 ) + ( 5 + 15 ) + ( 7 + 13 ) + ( 9 + 11 )
= 20 + 20 + 20 + 20 + 20
= 20 × 5 = 100
問７
8 + 7 ÷ 5 – 3 × 0 =
- 答え
- 9.4
- 解き方
- 8 + 7 ÷ 5 – 3 × 0
= 8 + 1.4 – 0 = 9.4
問８
128 ÷ { 8 + ( 5 × 3 – 42 ÷ 6 ) } =
- 答え
- 8
- 解き方
- 128 ÷ { 8 + ( 5 × 3 – 42 ÷ 6 ) }
= 128 ÷ { 8 + ( 15 – 7 ) }
= 128 ÷ ( 8 + 8 )
= 128 ÷ 16 = 8
問９
( 5 – 5 ÷ 2 ) × 6 – 5 ÷ ( 2 ÷ 5 ) – 12 ÷ 10 ÷ 2 =
- 答え
- 1.9 ( または、\(1\dfrac{9}{10}\) )
- 解き方
- ( 5 – 5 ÷ 2 ) × 6 – 5 ÷ ( 2 ÷ 5 ) – 12 ÷ 10 ÷ 2
= ( 5 – \(\dfrac{5}{2}\) ) × 6 – 5 ÷ \(\dfrac{2}{5}\) – 12 × \(\dfrac{1}{10}\) × \(\dfrac{1}{2}\)
= \(\dfrac{5}{2}\) × 6 – 5 × \(\dfrac{5}{2}\) – \(\dfrac{3}{5}\)
= 15 – \(\dfrac{25}{2}\) – \(\dfrac{3}{5}\)
= \(\dfrac{150\ -\ 125\ -\ 6}{10}\) = \(\dfrac{19}{10}\) = 1.9
問１０
10 × 9 – 8 ÷ 4 + 2 =
- 答え
- 90
- 解き方
- 10 × 9 – 8 ÷ 4 + 2
= 90 – 2 + 2 = 90
問１１
7 – 14 ÷ 42 × 9 =
- 答え
- 4
- 解き方
- 7 – 14 ÷ 42 × 9
= 7 – 14 × \(\dfrac{1}{42}\) × 9
= 7 – 3 = 4
問１２
9 – 2 × 4 + 10 ÷ 5 =
- 答え
- 3
- 解き方
- 9 – 2 × 4 + 10 ÷ 5
= 9 – 8 + 2 = 3
問１３
5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 + 21 + 23 =
- 答え
- 140
- 解き方
- 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 + 21 + 23
= ( 5 + 23 ) + ( 7 + 21 ) + ( 9 + 19 ) + ( 11 + 17 ) + ( 13 + 15 )
= 28 + 28 + 28 + 28 + 28
= 28 × 5 = 140
問１４
7 × 6 + 5 – 102 ÷ 6 =
- 答え
- 30
- 解き方
- 7 × 6 + 5 – 102 ÷ 6
= 42 + 5 – 17 = 30
問１５
( 12 × 7 – 16 × 3 ) ÷ ( 86 – 41 – 39 + 3 ) =
- 答え
- 4
- 解き方
- ( 12 × 7 – 16 × 3 ) ÷ ( 86 – 41 – 39 + 3 )
= ( 84 – 48 ) ÷ 9
= 36 ÷ 9 = 4
問１６
3 ÷ ( 6 ÷ 7 ) =
- 答え
- 3.5 ( または、\(3\dfrac{1}{2}\) )
- 解き方
- 3 ÷ ( 6 ÷ 7 )
= 3 ÷ \(\dfrac{6}{7}\)
= 3 × \(\dfrac{7}{6}\) = \(\dfrac{7}{2}\) = 3.5
問１７
( 9 – 5 ÷ 6 ) × 3 – ( 8 + 2 × 7 ) ÷ 4 =
- 答え
- 19
- 解き方
- ( 9 – 5 ÷ 6 ) × 3 – ( 8 + 2 × 7 ) ÷ 4
= ( 9 – \(\dfrac{5}{6}\) ) × 3 – ( 8 + 14 ) ÷ 4
= ( \(\dfrac{54}{6}\) – \(\dfrac{5}{6}\) ) × 3 – 22 ÷ 4
= \(\dfrac{49}{6}\) × 3 – \(\dfrac{22}{4}\)
= \(\dfrac{49}{2}\) – \(\dfrac{11}{2}\) = \(\dfrac{38}{2}\) = 19
問１８
32 ÷ 57 ÷ 25 × 95 ÷ 48 =
- 答え
- \(\dfrac{2}{45}\)
- 解き方
- 32 ÷ 57 ÷ 25 × 95 ÷ 48
= 32 × \(\dfrac{1}{57}\) × \(\dfrac{1}{25}\) × 95 × \(\dfrac{1}{48}\)
= \(\dfrac{32\ ×\ 95}{57\ ×\ 25\ ×\ 48}\)
= \(\dfrac{2\ ×\ 1}{3\ ×\ 5\ ×\ 3}\) = \(\dfrac{2}{45}\)
問１９
{ 7 + ( 8 – 2 ) × 10 } × 63 =
- 答え
- 4221
- 解き方
- { 7 + ( 8 – 2 ) × 10 } × 63
= ( 7 + 6 × 10 ) × 63
= ( 7 + 60 ) × 63
= 7 × 63 + 60 × 63
= 441 + 3780 = 4221
問２０
{ 2202 ÷ 6 – 201 ÷ ( 19 – 8 × 2 ) } ÷ 25 =
- 答え
- 12
- 解き方
- { 2202 ÷ 6 – 201 ÷ ( 19 – 8 × 2 ) } ÷ 25
= { 367 – 201 ÷ ( 19 – 16 ) } ÷ 25
= ( 367 – 201 ÷ 3 ) ÷ 25
= ( 367 – 67 ) ÷ 25
= 300 ÷ 25 = 12
問２１
112 – ( 6 × 19 – 81 ÷ 3 ) ÷ ( 54 ÷ 18 ) =
- 答え
- 83
- 解き方
- 112 – ( 6 × 19 – 81 ÷ 3 ) ÷ ( 54 ÷ 18 )
= 112 – ( 114 – 27 ) ÷ 3
= 112 – 87 ÷ 3
= 112 – 29 = 83
