問題
２つ以上の分数を比べるとき，通分する．
できるだけ分母を小さくするときは
８と６の最公数を出してから解くが，
ここでは簡単なたすきがけを使う．
たすきがけは，ちがう方の分数の分をかける．
| ５× |
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１× |
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| ————————— |
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————————— |
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| ８× |
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６× |
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| ——— |
， |
——— |
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こうすると分がそろうので分を見て大きさを比べられる．
まずは通分を練習する．
| ３ |
×２ |
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| ——— |
＝ |
——— |
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| ５ |
× |
１０ |
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| ２ |
× |
１０ |
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| ——— |
＝ |
——— |
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| ７ |
×５ |
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| ６ |
× |
１２ |
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| ——— |
＝ |
——— |
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| １１ |
× |
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| ３ |
× |
１２ |
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| ——— |
＝ |
——— |
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× |
３２ |
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| ６ |
× |
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| ——— |
＝ |
——— |
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| ７ |
× |
２１ |
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| ２ |
× |
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| ——— |
＝ |
——— |
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| ３ |
× |
２４ |
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大小関係を調べる．
| ３× |
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２× |
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| ————————— |
， |
————————— |
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| ８× |
|
７× |
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| ——— |
， |
——— |
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よって
| ３ |
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２ |
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| ——— |
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——— |
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| ８ |
|
７ |
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| ３× |
|
４× |
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| ————————— |
， |
————————— |
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| ５× |
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６× |
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| ————— |
， |
————— |
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| ３０ |
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３０ |
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よって
| ３ |
|
４ |
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| ——— |
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——— |
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| ５ |
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６ |
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| ３× |
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２× |
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| ————————— |
， |
————————— |
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| １１× |
|
７× |
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| ——— |
， |
——— |
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| ７７ |
|
７７ |
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よって
| ３ |
|
２ |
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| ——— |
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——— |
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| １１ |
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７ |
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