Ruling on tankees or altering the order of verses when memorising Quran
Question

I have a question regarding tankees. According to what I know, tankees is when you recite an ayah, huroof, words, and surahs. But, what I want to know is that is it haram to MEMORIZE it that way. eg: I used to memorize the quraan in a madrasah where we memorized this way: for example, if our teacher gave us ayah 1-5, surah hashr; we would start memorizing from: (transliteration)"wama qata'tum millinatin au tarak tumooha qa'imah" (finsh ayah and go to the one before it, we DIDN'T start from "sabbaha lillahi" and memorized backwards like that until we reached the first ayah. Of course, when we recited it to the sheikhafter memorizing, we said it in order, but is MEMORIZING while displacing the order "tankees"?.
Praise be to Allah.Tankees or altering the order of verses when reciting is haram, whether that is during prayer or otherwise. 
It says in Asna’l-Mataalib (1/63): It is haram to switch the order of verses when reciting, because that undermines the miraculous nature of the text and it ignores the wisdom behind the order in which the verses appear. End quote. 
It says in Haashiyat ad-Dasooqi (1/242): Switching the order of soorahs is makrooh, and switching the order of consecutive verses in one rak‘ah is haram and invalidates the prayer, because it distorts it. End quote. 
It says in Kashshaaf al-Qinaa‘ (1/343): It is makrooh to switch the order of soorahs, such as reciting al-Inshiraah (94), then reciting ad-Duha (93) after it, whether that is in one or two rak‘ahs, because of the report narrated from Ibn Mas‘ood, according to which he was asked about someone who recited Quran in the wrong order. He said: His heart is disordered. Abu ‘Ubayd explained that as referring to when a person recites one soorah, then after it he recites another that comes before it in the order (of soorahs in the Mushaf). This was mentioned by Ibn Nasrullah in ash-Sharh as being similar to the case with verses, that is, a similar ruling of it being makrooh applies in the case of switching the order of the verses. It says in al-Furoo‘ that there is consensus on this point. Ibn Nasrullah said: If it was said that it is haram to switch the order of verses, that would be a valid opinion. The evidence for it being only makrooh is not clear, and using as evidence the way the Prophet (blessings and peace of Allah be upon him) learned it is subject to further discussion, because that was due to need, as the Quran was revealed according to events. Shaykh [Ibn Taymiyah] said: Following the order of verses is obligatory, because the order in which they appear is based on clear instructions of the Prophet (blessings and peace of Allah be upon him), according to scholarly consensus. End quote. 
But if the switching of the order occurs when memorising, not when reciting or asking someone to listen so as to check one’s memorisation, there is nothing wrong with that. So one may begin by memorising the fifth verse, for example, then the fourth, then when one wants to recite them, one recites the fourth verse and then the fifth, without switching the order. Then when he has memorised the third, and he wants to recite what he had memorised, he should recite them in the proper order without switching it. So he should recite the third, then the fourth, then the fifth. There is nothing wrong with this; some teachers do it this way and think that it is the best way of memorising. 
To sum up: It is not permissible to recite two consecutive verses in the wrong order, and it is not permissible to switch the order of words in one verse. 
For more information please see the answer to question no. 7198  
And Allah knows best.