يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوٓا۟ إِنَّمَا ٱلْخَمْرُ وَٱلْمَيْسِرُ وَٱلْأَنصَابُ وَٱلْأَزْلَٰمُ رِجْسٌۭ مِّنْ عَمَلِ ٱلشَّيْطَٰنِ فَٱجْتَنِبُوهُ لَعَلَّكُمْ تُفْلِحُونَ ﴿٩٠﴾
信道的人们啊! 饮酒、赌博、拜像、求签，只是一种秽行，只是恶魔的行为，故当远离，以便你们成功。
Haram Money & business
Is gambling haram?
Short answer
Yes. The Quran counts gambling (maysir) with intoxicants as an abomination of Satan's work and commands us to avoid it (5:90). It also says that in them there is great sin and some benefit, but their sin is greater than their benefit (2:219).
Evidence
Quran
إِنَّمَا يُرِيدُ ٱلشَّيْطَٰنُ أَن يُوقِعَ بَيْنَكُمُ ٱلْعَدَٰوَةَ وَٱلْبَغْضَآءَ فِى ٱلْخَمْرِ وَٱلْمَيْسِرِ وَيَصُدَّكُمْ عَن ذِكْرِ ٱللَّهِ وَعَنِ ٱلصَّلَوٰةِ ۖ فَهَلْ أَنتُم مُّنتَهُونَ ﴿٩١﴾
恶魔惟愿你们因饮酒和赌博而互相仇恨，并且阻止你们记念真主，和谨守拜功。你们将戒除（饮酒和赌博）吗﹖
۞ يَسْـَٔلُونَكَ عَنِ ٱلْخَمْرِ وَٱلْمَيْسِرِ ۖ قُلْ فِيهِمَآ إِثْمٌۭ كَبِيرٌۭ وَمَنَٰفِعُ لِلنَّاسِ وَإِثْمُهُمَآ أَكْبَرُ مِن نَّفْعِهِمَا ۗ وَيَسْـَٔلُونَكَ مَاذَا يُنفِقُونَ قُلِ ٱلْعَفْوَ ۗ كَذَٰلِكَ يُبَيِّنُ ٱللَّهُ لَكُمُ ٱلْءَايَٰتِ لَعَلَّكُمْ تَتَفَكَّرُونَ ﴿٢١٩﴾
他们问你饮酒和赌博（的律例），你说：这两件事都包含著大罪，对於世人都有许多利益，而其罪过比利益还大。他们问你他们应该施舍甚麽，你说：你们施舍剩余的吧。真主这样为你们阐明一切迹象，以便你们思维今世和後世的事务。
This is general information, not a fatwa. For your own situation, ask a qualified scholar.
Questions about halal and haram
Is gambling haram?
Yes. The Quran counts gambling (maysir) with intoxicants as an abomination of Satan's work and commands us to avoid it (5:90). It also says that in them there is great sin and some benefit, but their sin is greater than their benefit (2:219).