A, fractional multiplication:

1, fraction multiplied by integer: the product of numerator multiplied by Jing Quan is numerator, and the denominator remains unchanged.

2. Fraction multiplied by fraction: take the product of rough molecular system as numerator and the product of denominator as denominator.

3, simple calculation: energy can be divided first and then calculated; When calculating the score by energy method, it is necessary to change the sub-payment into the development score and then calculate it.

Second, solve the problem:

1. Find the fraction of a number.

It's a bit complicated to find the score of a number.

Third, the countdown:

1 and the concept of reciprocal: two numbers whose product is 1 are reciprocal; Reciprocal is the relationship between two numbers, which are interdependent and cannot exist alone; The reciprocal of 1 is1; 0 has no reciprocal.

2. Reciprocal method: find the decimal fraction and exchange the positions of numerator and denominator; Find the reciprocal of an integer, treat this integer as a fraction with a denominator of 1, and then exchange the positions of the denominator of the numerator; Find the reciprocal of the band score, turn the band score into a false score, and then find the reciprocal; Find the reciprocal of the decimal, turn the decimal into a fraction, and then find the reciprocal.

Expand knowledge:

Introduction to mathematics;

Mathematics [English: Mathematics, derived from the ancient Greek μ θ η μ α (má th ē ma); Often abbreviated as math or maths], it is a discipline that studies concepts such as quantity, structure, change, space and information. Mathematics is a universal means for human beings to strictly describe the abstract structure and mode of things, and can be applied to any problem in the real world.

All mathematical objects are artificially defined in essence. In this sense, mathematics belongs to formal science, not natural science. Different mathematicians and philosophers have a series of views on the exact scope and definition of mathematics. Mathematics plays an irreplaceable role in the development of human history and social life, and it is also an indispensable basic tool for studying and studying modern science and technology.