小5數學題!急~20點(異分母分數+-混合)

1. 2又1/5+2又1/4-3又1/2
=11/5+9/4-7/2
=44/20+45/20-70/20
=19/20
2. 5又3/4-1又2/3+3又1/2
=23/4-5/3+7/2
=69/12-20/12+42/12
=91/12
3. 172又5/6-751/2+42又2/3
=1037/6-751/2+128/3
=2074/12-4506/12+512/12
= -1920/12
=160
4. 34又3/4-5又5/8+34又3/4
=139/4-45/8+139/4
=278/8-45/8+278/8
=511/8

唔知系唔系都岩曬~ 話曬手算 xd
加油呀~ 瞭解之中嘅計算方法就計得熟咖啦~ 記得約簡啊！

2010-10-22 17:42:15 補充：
第3題你個751/2冇打錯咖呵？系假分數啊呵？

自己功課要自己努力！同意樓上
唔好靠上網問哦~

1. 2又1/5+2又1/4-3又1/2
=11/5+9/4-7/2
=44/20+45/20-70/20
=19/20
2. 5又3/4-1又2/3+3又1/2
=23/4-5/3+7/2
=69/12-20/12+42/12
=91/12
3. 172又5/6-751/2+42又2/3
=1037/6-751/2+128/3
=2074/12-4506/12+512/12
= -1920/12
=160
4. 34又3/4-5又5/8+34又3/4
=139/4-45/8+139/4
=278/8-45/8+278/8
=511/8

. 2又1/5+2又1/4-3又1/2
=11/5+9/4-7/2
=44/20+45/20-70/20
=19/20
2. 5又3/4-1又2/3+3又1/2
=23/4-5/3+7/2
=69/12-20/12+42/12
=91/12
3. 172又5/6-751/2+42又2/3
=1037/6-751/2+128/3
=2074/12-4506/12+512/12
= -1920/12
=160
4. 34又3/4-5又5/8+34又3/4
=139/4-45/8+139/4
=278/8-45/8+278/8
=511/8
下次自己計啦
考試加油>_<

1. 2又1/5+2又1/4-3又1/2
=11/5+9/4-7/2
=44/20+45/20-70/20
=19/20
2. 5又3/4-1又2/3+3又1/2
=23/4-5/3+7/2
=69/12-20/12+42/12
=91/12
3. 172又5/6-751/2+42又2/3
=1037/6-751/2+128/3
=2074/12-4506/12+512/12
= -1920/12
=160
4. 34又3/4-5又5/8+34又3/4
=139/4-45/8+139/4
=278/8-45/8+278/8
=511/8

自己D功課要自己做!我都想幫你,不過我唔係好明你寫咩!Sorry!