The theme of the Quran revolves around the unity of God. The mathematics of the Quran is designed as a formidable mechanism to guard against any distortion attributed to God. Case in example is the two false verses, 9:128 and 9:129 rejected by the Ultimate Mathematics of the Quran.
Let us list all frequencies of the word one referred to God.
1) 2:163 And your god is one god. There is no god except He, The All Gracious, The All Merciful.
2) 4:171 O people of the scripture, do not transgress the limits of your religion, and do not say about God other than the truth. The Messiah, Jesus, the son of Mary, was a messenger of God, and His word that He had sent to Mary, and a spirit from Him. Therefore, you shall believe in God and His messengers, and do not say, trinity. Stop, for your own good. Indeed God is one god. Be He glorified, much too high to have a son. To Him belongs everything in the skies and everything on the land. God suffices as Lord and master.
4) 6:19 Say, whose testimony is the greatest? Say, Gods. He is the witness between me, and you that this Quran has been inspired to me, to preach it to you and whomever it reaches. Indeed, you set up other gods besides God. Say, I do not testify as you do. There is only one god and I disown your act of setting up partners.
5) 12:39 O my prison mates, is it better to worship several gods, or God, The One, the Supreme?
6) 13:16 Say, who is the Lord of the skies and the land? Say, God. Say, why then do you set up masters besides Him, who do not possess any power to benefit or harm even themselves? Say, is the blind the same as the seer? Is darkness the same as the light? Have they found partners besides God who created creations similar to His creations, to the point of not distinguishing the two creations? Say, God is the Creator of all things. He is The One, the Supreme.
7) 14:48 The day will come when this land will be substituted with a new land, and also the skies, and everyone will be brought before God , The One, the Supreme.
8) 14:52 This is a proclamation for the people, to be warned herewith, that they may know that He is only one god. Those who possess intelligence will take heed.
9) 16:22 Your god is one god. As for those who do not believe in the Hereafter, their hearts are denying and they are arrogant.
10) 16:51 God has proclaimed: Do not worship two gods; there is only one god. Therefore, you shall reverence Me alone.
11) 18:110 Say, I am no more than a human like you, being inspired that your god is one god. Those who hope to meet their Lord shall work righteousness, and never worship any other god besides his Lord.
12) 21:108 Proclaim, I have been given divine inspiration that your god is one god. Will you then submit?
13) 22:34 For each congregation We have decreed a ritual whereby they commemorate the name of God for providing them with the lifestock. Your god is one and the same god; you shall all submit to Him. Give good news to the obedient.
14) 29:46 Do not argue with the people of the scripture except in the nicest possible manner unless they transgress and say, We believe in what was revealed to us and what was revealed to you, and our god and your god is one and the same; to Him we are Muslims.
15) 37:4 Your god is only one.
16) 38:65 Say, I warn you; there in no other god besides God, The One, The Supreme.
17) 39:4 If God wanted to have a son, He could have chosen whomever He willed from among His creation. Be He glorified; He is God, The One, The Supreme.
18) 40:16 That is the day when they will be completely exposed; none of them will hide anything from God. To whom belongs all kingship on that day? To God, The One, The Supreme.
19) 41:6 Say, I am no more than a human being like you, being inspired that your god is one god. You shall be devoted to Him, and ask His forgiveness. Woe to those who set up partners.
As you see these verses are warning about the gravity of not believing in the oneness of God. Furthermore, you note that believing in the oneness of God is divinely inspired and cannot be taught to people who are not inspired by God to do so.