1. 123+234+456=357+456=8 18; 32 1+234+567=555+567= 1 122; 20 1+285+345=486+345=83 1; 345+32 1+4 12=667+4 1 1= 1078; 23 1+547+25 1=778+25 1= 1029

2.988- 124-32 1=863-320=543; 897- 154-23 1=743-23 1=5 12; 789- 123-234=666-234=432; 900- 100-600=800-600=200; 675- 12 1-32 1=554-32 1=233

3. Addition and subtraction sequence: calculated in sequence. If the same formula only has addition and subtraction, it can be calculated by a simple method, that is, the last one is calculated by rounding first, and then the previous one is added or subtracted.

Applied computing and human beings, because of the wide variety of modern human disciplines, involve a wide range, fine classification. Nowadays, every subject needs a lot of calculation.

Astronomical research institutions need computers to analyze space pulses and star position movements; Biologists need computers to simulate protein's folding process and discover the mystery of the genome. Pharmacists want to develop drugs to treat cancer or various bacteria and viruses, and medical scientists are developing new ways to prevent aging;

Mathematicians hope to calculate the largest prime number and more accurate value of π; Economists should use computer analysis to calculate the development direction of an enterprise/city/country under the consideration of tens of thousands of factors in order to carry out macro-control; Industry needs to accurately calculate the best scheme of material, energy, processing and time allocation in the production process.

It can be seen that the future science of mankind is inseparable from calculation all the time. Distributed computing has attracted more and more attention from the society because of its unique advantages-low cost and high efficiency.

Calculation is not only the basic skill of mathematics, but also the tool of the whole natural science. When studying at school, you must master the basic survival skills of computing; In scientific research, we must use calculation to complete the key problems of research; The breakthrough development of national economy, computer and electronic industry must be based on mathematical calculation. Therefore, computing is the main method in basic education, and it is widely used in various disciplines, high-performance computing and other advanced technologies.

Generalized calculation includes mathematical calculation, logical reasoning, grammar generation, set theory function, arrangement of combinatorial mathematics, variable replacement, graphic image transformation, mathematical statistics and so on. The traversal of artificial intelligence solution space, problem solving, path problem of graph theory, network security, algebraic system theory, context representation perception and reasoning, intelligent space, etc. Even including digital system design, software programming, robot design, architectural design and other design issues.