Hello aspirant

You will have to prepare on topics like general awareness, general mental ability , numerical ability , comprehension and conceptual awareness of the subjects including plants, Environment, health and pollution, human body , common disease, population explosion, solar energy, natural resources and industry .

For more information you can refer following link

https://university.careers360.com/articles/bhu-uet-exam-pattern

hi,

the numerical ability question generally comes from 10th standard mathematics, you may follow your 10th mathematics books or objective mathematics  books by amitabh mitra or numerical aptitude by disha experts.