Mathematics is my favorite subject in school days. I deals with quantity, structure and space
I like geometry but not algebra.  What is your favorite math?
I like both geometry and algebra in mathematics 
Is calculus a good subject to learn?
Yes Definitely it is the good choice to learn and one of the important structure in mathematics subject
Can I learn math subjects just by reading a book or do I need a teacher?
Mathematics
Mathematics (from Greek μάθημα "máthēma", "knowledge, study, learning") includes the study of such topics as quantity (number theory), structure (algebra), space (geometry), and change (mathematical analysis). It has no generally accepted definition.
Mathematicians seek and use patterns to formulate new conjectures; they resolve the truth or falsity of conjectures by mathematical proof. When mathematical structures are good models of real phenomena, then mathematical reasoning can provide insight or predictions about nature.
SAT Subject Test in Mathematics Level 1
The SAT Subject Test in Mathematics Level 1 (formerly known as Math I or MathIC (the "C" representing the use of a calculator)) is the name of a one-hour multiple choice test given on algebra, geometry, basic trigonometry, algebraic functions, elementary statistics and basic foundations of calculus by The College Board. A student chooses whether to take the test depending upon college entrance requirements for the schools in which the student is planning to apply. Until 1994,