I have a family member who wants to give some competitive exams. The quant portions of these exams require a good grasp on basic math skills like factoring out, adding/subtracting equations, basic polynomial factoring, simplifying fractions, etc. An example is factoring out $\sqrt\pi$ from this expression like so: $$5\sqrt\pi+\frac{9}{2\sqrt\pi}=\sqrt\pi\bigg(5+\frac{9}{2\pi}\bigg)$$
Currently they're struggling with factoring out of the above form. I'd be really grateful if you I can get good books or resources where they can extensively practice math skills like the above - with tons of practice problems and solutions. Thanks in advance!
I would recommend "Mathematics for the Practical Man” by George Howe, but i guess it doesn't have enough practice problems to get a really good grasp.
If you are looking for a textbook with good theory for absolute beginners, solved examples and practice questions with solutions go for NCERT Mathematics textbook Class 8 to NCERT Mathematics textbook class 10 (No calculus) And the NCERT maths for classes 11 and 12 for basic calculus.
You should thoroughly check out the online pdf for NCERT Maths class 8 to see if it actually meets your requirements. Detailed solutions and explanation of ncert maths are available online. And after having mastered concepts from the NCERT book, you can try RD Sharma maths class 8, which is basically a book containing only questions and solutions based on concepts from ncert.
let me know if it helps (NCERT maths Books are used by indian cbse board schools so it will cover all basic requirements for maths)