It’s problematic.
Reading just from those lines, you can make a very easy reading that it’s just a matter of the key phrase being “in order to be seen” - like the others have said, it’s about doing something for the purpose of looking good, and not for the sake of actually being good. But it isn’t as simple as that;
[QUOTE=Matthew 6:1-8 NIV]
6 “Be careful not to practice your righteousness in front of others to be seen by them. If you do, you will have no reward from your Father in heaven.
2 “So when you give to the needy, do not announce it with trumpets, as the hypocrites do in the synagogues and on the streets, to be honored by others. Truly I tell you, they have received their reward in full. 3 But when you give to the needy, do not let your left hand know what your right hand is doing, 4 so that your giving may be in secret. Then your Father, who sees what is done in secret, will reward you.
Prayer
5 “And when you pray, do not be like the hypocrites, for they love to pray standing in the synagogues and on the street corners to be seen by others. Truly I tell you, they have received their reward in full. 6 But when you pray, go into your room, close the door and pray to your Father, who is unseen. Then your Father, who sees what is done in secret, will reward you. 7 And when you pray, do not keep on babbling like pagans, for they think they will be heard because of their many words. 8 Do not be like them, for your Father knows what you need before you ask him.
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There actually is suggesting that this kind of good behaviour SHOULD be entirely secret, or as secret as possible. After the part I’ve quoted you get the Lord’s Prayer, and then after that there’s another section on fasting which, again, suggests that care should be taken to ensure that no-one even knows you’re doing it.
I think what’s most illuminating about this question (sorry for the pun), is that in each section the same terms are used at one point;
[QUOTE=Matthew 6:22-24 NIV]
22 “The eye is the lamp of the body. If your eyes are healthy your whole body will be full of light. 23 But if your eyes are unhealthy, your whole body will be full of darkness. If then the light within you is darkness, how great is that darkness!
24 “No one can serve two masters. Either you will hate the one and love the other, or you will be devoted to the one and despise the other. You cannot serve both God and money.
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[QUOTE=Matthew 5:14-16 NIV]
14 “You are the light of the world. A town built on a hill cannot be hidden. 15 Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house. 16 In the same way, let your light shine before others, that they may see your good deeds and glorify your Father in heaven.
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It isn’t easily interpreted to me, sadly. But I would make a loose guess that the idea here is that if you do good deeds, people will be able to tell simply because of how that will affect you. So you shouldn’t do your good deeds in public - you should take steps, in fact, to keep them as secret as possible. Because what’s going to speak for you isn’t those deeds, but how that goodness emanates from you.